+++ /dev/null
- Python 2.3 Quick Reference
-
-
- 25 Jan 2003 upgraded by Raymond Hettinger for Python 2.3
- 16 May 2001 upgraded by Richard Gruet and Simon Brunning for Python 2.0
- 2000/07/18 upgraded by Richard Gruet, rgruet@intraware.com for Python 1.5.2
-from V1.3 ref
-1995/10/30, by Chris Hoffmann, choffman@vicorp.com
-
-Based on:
- Python Bestiary, Author: Ken Manheimer, ken.manheimer@nist.gov
- Python manuals, Authors: Guido van Rossum and Fred Drake
- What's new in Python 2.0, Authors: A.M. Kuchling and Moshe Zadka
- python-mode.el, Author: Tim Peters, tim_one@email.msn.com
-
- and the readers of comp.lang.python
-
-Python's nest: http://www.python.org Developement: http://
-python.sourceforge.net/ ActivePython : http://www.ActiveState.com/ASPN/
-Python/
-newsgroup: comp.lang.python Help desk: help@python.org
-Resources: http://starship.python.net/
- http://www.vex.net/parnassus/
- http://aspn.activestate.com/ASPN/Cookbook/Python
-FAQ: http://www.python.org/cgi-bin/faqw.py
-Full documentation: http://www.python.org/doc/
-Excellent reference books:
- Python Essential Reference by David Beazley (New Riders)
- Python Pocket Reference by Mark Lutz (O'Reilly)
-
-
-Invocation Options
-
-python [-diOStuUvxX?] [-c command | script | - ] [args]
-
- Invocation Options
-Option Effect
--c cmd program passed in as string (terminates option list)
--d Outputs parser debugging information (also PYTHONDEBUG=x)
--E ignore environment variables (such as PYTHONPATH)
--h print this help message and exit
--i Inspect interactively after running script (also PYTHONINSPECT=x) and
- force prompts, even if stdin appears not to be a terminal
--m mod run library module as a script (terminates option list
--O optimize generated bytecode (a tad; also PYTHONOPTIMIZE=x)
--OO remove doc-strings in addition to the -O optimizations
--Q arg division options: -Qold (default), -Qwarn, -Qwarnall, -Qnew
--S Don't perform 'import site' on initialization
--u Unbuffered binary stdout and stderr (also PYTHONUNBUFFERED=x).
--v Verbose (trace import statements) (also PYTHONVERBOSE=x)
--W arg : warning control (arg is action:message:category:module:lineno)
--x Skip first line of source, allowing use of non-unix Forms of #!cmd
--? Help!
--c Specify the command to execute (see next section). This terminates the
-command option list (following options are passed as arguments to the command).
- the name of a python file (.py) to execute read from stdin.
-script Anything afterward is passed as options to python script or command,
- not interpreted as an option to interpreter itself.
-args passed to script or command (in sys.argv[1:])
- If no script or command, Python enters interactive mode.
-
- * Available IDEs in std distrib: IDLE (tkinter based, portable), Pythonwin
- (Windows).
-
-
-
-Environment variables
-
- Environment variables
- Variable Effect
-PYTHONHOME Alternate prefix directory (or prefix;exec_prefix). The
- default module search path uses prefix/lib
- Augments the default search path for module files. The format
- is the same as the shell's $PATH: one or more directory
- pathnames separated by ':' or ';' without spaces around
- (semi-)colons!
-PYTHONPATH On Windows first search for Registry key HKEY_LOCAL_MACHINE\
- Software\Python\PythonCore\x.y\PythonPath (default value). You
- may also define a key named after your application with a
- default string value giving the root directory path of your
- app.
- If this is the name of a readable file, the Python commands in
-PYTHONSTARTUP that file are executed before the first prompt is displayed in
- interactive mode (no default).
-PYTHONDEBUG If non-empty, same as -d option
-PYTHONINSPECT If non-empty, same as -i option
-PYTHONSUPPRESS If non-empty, same as -s option
-PYTHONUNBUFFERED If non-empty, same as -u option
-PYTHONVERBOSE If non-empty, same as -v option
-PYTHONCASEOK If non-empty, ignore case in file/module names (imports)
-
-
-
-
-Notable lexical entities
-
-Keywords
-
- and del for is raise
- assert elif from lambda return
- break else global not try
- class except if or while
- continue exec import pass yield
- def finally in print
-
- * (list of keywords in std module: keyword)
- * Illegitimate Tokens (only valid in strings): @ $ ?
- * A statement must all be on a single line. To break a statement over
- multiple lines use "\", as with the C preprocessor.
- Exception: can always break when inside any (), [], or {} pair, or in
- triple-quoted strings.
- * More than one statement can appear on a line if they are separated with
- semicolons (";").
- * Comments start with "#" and continue to end of line.
-
-Identifiers
-
- (letter | "_") (letter | digit | "_")*
-
- * Python identifiers keywords, attributes, etc. are case-sensitive.
- * Special forms: _ident (not imported by 'from module import *'); __ident__
- (system defined name);
- __ident (class-private name mangling)
-
-Strings
-
- "a string enclosed by double quotes"
- 'another string delimited by single quotes and with a " inside'
- '''a string containing embedded newlines and quote (') marks, can be
- delimited with triple quotes.'''
- """ may also use 3- double quotes as delimiters """
- u'a unicode string' U"Another unicode string"
- r'a raw string where \ are kept (literalized): handy for regular
- expressions and windows paths!'
- R"another raw string" -- raw strings cannot end with a \
- ur'a unicode raw string' UR"another raw unicode"
-
- Use \ at end of line to continue a string on next line.
- adjacent strings are concatened, e.g. 'Monty' ' Python' is the same as
- 'Monty Python'.
- u'hello' + ' world' --> u'hello world' (coerced to unicode)
-
- String Literal Escapes
-
- \newline Ignored (escape newline)
- \\ Backslash (\) \e Escape (ESC) \v Vertical Tab (VT)
- \' Single quote (') \f Formfeed (FF) \OOO char with octal value OOO
- \" Double quote (") \n Linefeed (LF)
- \a Bell (BEL) \r Carriage Return (CR) \xHH char with hex value HH
- \b Backspace (BS) \t Horizontal Tab (TAB)
- \uHHHH unicode char with hex value HHHH, can only be used in unicode string
- \UHHHHHHHH unicode char with hex value HHHHHHHH, can only be used in unicode string
- \AnyOtherChar is left as-is
-
- * NUL byte (\000) is NOT an end-of-string marker; NULs may be embedded in
- strings.
- * Strings (and tuples) are immutable: they cannot be modified.
-
-Numbers
-
- Decimal integer: 1234, 1234567890546378940L (or l)
- Octal integer: 0177, 0177777777777777777 (begin with a 0)
- Hex integer: 0xFF, 0XFFFFffffFFFFFFFFFF (begin with 0x or 0X)
- Long integer (unlimited precision): 1234567890123456
- Float (double precision): 3.14e-10, .001, 10., 1E3
- Complex: 1J, 2+3J, 4+5j (ends with J or j, + separates (float) real and
- imaginary parts)
-
-Sequences
-
- * String of length 0, 1, 2 (see above)
- '', '1', "12", 'hello\n'
- * Tuple of length 0, 1, 2, etc:
- () (1,) (1,2) # parentheses are optional if len > 0
- * List of length 0, 1, 2, etc:
- [] [1] [1,2]
-
-Indexing is 0-based. Negative indices (usually) mean count backwards from end
-of sequence.
-
-Sequence slicing [starting-at-index : but-less-than-index]. Start defaults to
-'0'; End defaults to 'sequence-length'.
-
-a = (0,1,2,3,4,5,6,7)
- a[3] ==> 3
- a[-1] ==> 7
- a[2:4] ==> (2, 3)
- a[1:] ==> (1, 2, 3, 4, 5, 6, 7)
- a[:3] ==> (0, 1, 2)
- a[:] ==> (0,1,2,3,4,5,6,7) # makes a copy of the sequence.
-
-Dictionaries (Mappings)
-
- {} # Zero length empty dictionary
- {1 : 'first'} # Dictionary with one (key, value) pair
- {1 : 'first', 'next': 'second'}
- dict([('one',1),('two',2)]) # Construct a dict from an item list
- dict('one'=1, 'two'=2) # Construct a dict using keyword args
- dict.fromkeys(['one', 'keys']) # Construct a dict from a sequence
-
-Operators and their evaluation order
-
- Operators and their evaluation order
-Highest Operator Comment
- (...) [...] {...} `...` Tuple, list & dict. creation; string
- conv.
- s[i] s[i:j] s.attr f(...) indexing & slicing; attributes, fct
- calls
- +x, -x, ~x Unary operators
- x**y Power
- x*y x/y x%y x//y mult, division, modulo, floor division
- x+y x-y addition, subtraction
- x<<y x>>y Bit shifting
- x&y Bitwise and
- x^y Bitwise exclusive or
- x|y Bitwise or
- x<y x<=y x>y x>=y x==y x!=y Comparison,
- x is y x is not y membership
- x in s x not in s
- not x boolean negation
- x and y boolean and
- x or y boolean or
-Lowest lambda args: expr anonymous function
-
-Alternate names are defined in module operator (e.g. __add__ and add for +)
-Most operators are overridable.
-
-Many binary operators also support augmented assignment:
- x += 1 # Same as x = x + 1
-
-
-Basic Types and Their Operations
-
-Comparisons (defined between *any* types)
-
- Comparisons
-Comparison Meaning Notes
-< strictly less than (1)
-<= less than or equal to
-> strictly greater than
->= greater than or equal to
-== equal to
-!= not equal to
-is object identity (2)
-is not negated object identity (2)
-
-Notes :
- Comparison behavior can be overridden for a given class by defining special
-method __cmp__.
- The above comparisons return True or False which are of type bool
-(a subclass of int) and behave exactly as 1 or 0 except for their type and
-that they print as True or False instead of 1 or 0.
- (1) X < Y < Z < W has expected meaning, unlike C
- (2) Compare object identities (i.e. id(object)), not object values.
-
-Boolean values and operators
-
- Boolean values and operators
- Value or Operator Returns Notes
-None, numeric zeros, empty sequences and False
-mappings
-all other values True
-not x True if x is False, else
- True
-x or y if x is False then y, else (1)
- x
-x and y if x is False then x, else (1)
- y
-
-Notes :
- Truth testing behavior can be overridden for a given class by defining
-special method __bool__.
- (1) Evaluate second arg only if necessary to determine outcome.
-
-None
-
- None is used as default return value on functions. Built-in single object
- with type NoneType.
- Input that evaluates to None does not print when running Python
- interactively.
-
-Numeric types
-
-Floats and integers.
-
- Floats are implemented with C doubles.
- Integers have unlimited size (only limit is system resources)
-
-Operators on all numeric types
-
- Operators on all numeric types
- Operation Result
-abs(x) the absolute value of x
-int(x) x converted to integer
-float(x) x converted to floating point
--x x negated
-+x x unchanged
-x + y the sum of x and y
-x - y difference of x and y
-x * y product of x and y
-x / y quotient of x and y
-x % y remainder of x / y
-divmod(x, y) the tuple (x/y, x%y)
-x ** y x to the power y (the same as pow(x, y))
-
-Bit operators on integers
-
- Bit operators
-Operation >Result
-~x the bits of x inverted
-x ^ y bitwise exclusive or of x and y
-x & y bitwise and of x and y
-x | y bitwise or of x and y
-x << n x shifted left by n bits
-x >> n x shifted right by n bits
-
-Complex Numbers
-
- * represented as a pair of machine-level double precision floating point
- numbers.
- * The real and imaginary value of a complex number z can be retrieved through
- the attributes z.real and z.imag.
-
-Numeric exceptions
-
-TypeError
- raised on application of arithmetic operation to non-number
-OverflowError
- numeric bounds exceeded
-ZeroDivisionError
- raised when zero second argument of div or modulo op
-FloatingPointError
- raised when a floating point operation fails
-
-Operations on all sequence types (lists, tuples, strings)
-
- Operations on all sequence types
-Operation Result Notes
-x in s True if an item of s is equal to x, else False
-x not in s False if an item of s is equal to x, else True
-for x in s: loops over the sequence
-s + t the concatenation of s and t
-s * n, n*s n copies of s concatenated
-s[i] i'th item of s, origin 0 (1)
-s[i:j] slice of s from i (included) to j (excluded) (1), (2)
-len(s) length of s
-min(s) smallest item of s
-max(s) largest item of (s)
-iter(s) returns an iterator over s. iterators define __iter__ and next()
-
-Notes :
- (1) if i or j is negative, the index is relative to the end of the string,
-ie len(s)+ i or len(s)+j is
- substituted. But note that -0 is still 0.
- (2) The slice of s from i to j is defined as the sequence of items with
-index k such that i <= k < j.
- If i or j is greater than len(s), use len(s). If i is omitted, use
-len(s). If i is greater than or
- equal to j, the slice is empty.
-
-Operations on mutable (=modifiable) sequences (lists)
-
- Operations on mutable sequences
- Operation Result Notes
-s[i] =x item i of s is replaced by x
-s[i:j] = t slice of s from i to j is replaced by t
-del s[i:j] same as s[i:j] = []
-s.append(x) same as s[len(s) : len(s)] = [x]
-s.count(x) return number of i's for which s[i] == x
-s.extend(x) same as s[len(s):len(s)]= x
-s.index(x) return smallest i such that s[i] == x (1)
-s.insert(i, x) same as s[i:i] = [x] if i >= 0
-s.pop([i]) same as x = s[i]; del s[i]; return x (4)
-s.remove(x) same as del s[s.index(x)] (1)
-s.reverse() reverse the items of s in place (3)
-s.sort([cmpFct]) sort the items of s in place (2), (3)
-
-Notes :
- (1) raise a ValueError exception when x is not found in s (i.e. out of
-range).
- (2) The sort() method takes an optional argument specifying a comparison
-fct of 2 arguments (list items) which should
- return -1, 0, or 1 depending on whether the 1st argument is
-considered smaller than, equal to, or larger than the 2nd
- argument. Note that this slows the sorting process down considerably.
- (3) The sort() and reverse() methods modify the list in place for economy
-of space when sorting or reversing a large list.
- They don't return the sorted or reversed list to remind you of this
-side effect.
- (4) [New 1.5.2] The optional argument i defaults to -1, so that by default the last
-item is removed and returned.
-
-
-
-Operations on mappings (dictionaries)
-
- Operations on mappings
- Operation Result Notes
-len(d) the number of items in d
-d[k] the item of d with key k (1)
-d[k] = x set d[k] to x
-del d[k] remove d[k] from d (1)
-d.clear() remove all items from d
-d.copy() a shallow copy of d
-d.get(k,defaultval) the item of d with key k (4)
-d.has_key(k) True if d has key k, else False
-d.items() a copy of d's list of (key, item) pairs (2)
-d.iteritems() an iterator over (key, value) pairs (7)
-d.iterkeys() an iterator over the keys of d (7)
-d.itervalues() an iterator over the values of d (7)
-d.keys() a copy of d's list of keys (2)
-d1.update(d2) for k, v in d2.items(): d1[k] = v (3)
-d.values() a copy of d's list of values (2)
-d.pop(k) remove d[k] and return its value
-d.popitem() remove and return an arbitrary (6)
- (key, item) pair
-d.setdefault(k,defaultval) the item of d with key k (5)
-
- Notes :
- TypeError is raised if key is not acceptable
- (1) KeyError is raised if key k is not in the map
- (2) Keys and values are listed in random order
- (3) d2 must be of the same type as d1
- (4) Never raises an exception if k is not in the map, instead it returns
- defaultVal.
- defaultVal is optional, when not provided and k is not in the map,
- None is returned.
- (5) Never raises an exception if k is not in the map, instead it returns
- defaultVal, and adds k to map with value defaultVal. defaultVal is
- optional. When not provided and k is not in the map, None is returned and
- added to map.
- (6) Raises a KeyError if the dictionary is emtpy.
- (7) While iterating over a dictionary, the values may be updated but
- the keys cannot be changed.
-
-Operations on strings
-
-Note that these string methods largely (but not completely) supersede the
-functions available in the string module.
-
-
- Operations on strings
- Operation Result Notes
-s.capitalize() return a copy of s with only its first character
- capitalized.
-s.center(width) return a copy of s centered in a string of length width (1)
- .
-s.count(sub[ return the number of occurrences of substring sub in (2)
-,start[,end]]) string s.
-s.decode(([ return a decoded version of s. (3)
- encoding
- [,errors]])
-s.encode([ return an encoded version of s. Default encoding is the
- encoding current default string encoding. (3)
- [,errors]])
-s.endswith(suffix return true if s ends with the specified suffix, (2)
- [,start[,end]]) otherwise return False.
-s.expandtabs([ return a copy of s where all tab characters are (4)
-tabsize]) expanded using spaces.
-s.find(sub[,start return the lowest index in s where substring sub is (2)
-[,end]]) found. Return -1 if sub is not found.
-s.index(sub[ like find(), but raise ValueError when the substring is (2)
-,start[,end]]) not found.
-s.isalnum() return True if all characters in s are alphanumeric, (5)
- False otherwise.
-s.isalpha() return True if all characters in s are alphabetic, (5)
- False otherwise.
-s.isdigit() return True if all characters in s are digit (5)
- characters, False otherwise.
-s.islower() return True if all characters in s are lowercase, False (6)
- otherwise.
-s.isspace() return True if all characters in s are whitespace (5)
- characters, False otherwise.
-s.istitle() return True if string s is a titlecased string, False (7)
- otherwise.
-s.isupper() return True if all characters in s are uppercase, False (6)
- otherwise.
-s.join(seq) return a concatenation of the strings in the sequence
- seq, separated by 's's.
-s.ljust(width) return s left justified in a string of length width. (1),
- (8)
-s.lower() return a copy of s converted to lowercase.
-s.lstrip() return a copy of s with leading whitespace removed.
-s.replace(old, return a copy of s with all occurrences of substring (9)
-new[, maxsplit]) old replaced by new.
-s.rfind(sub[ return the highest index in s where substring sub is (2)
-,start[,end]]) found. Return -1 if sub is not found.
-s.rindex(sub[ like rfind(), but raise ValueError when the substring (2)
-,start[,end]]) is not found.
-s.rjust(width) return s right justified in a string of length width. (1),
- (8)
-s.rstrip() return a copy of s with trailing whitespace removed.
-s.split([sep[ return a list of the words in s, using sep as the (10)
-,maxsplit]]) delimiter string.
-s.splitlines([ return a list of the lines in s, breaking at line (11)
-keepends]) boundaries.
-s.startswith return true if s starts with the specified prefix,
-(prefix[,start[ otherwise return false. (2)
-,end]])
-s.strip() return a copy of s with leading and trailing whitespace
- removed.
-s.swapcase() return a copy of s with uppercase characters converted
- to lowercase and vice versa.
- return a titlecased copy of s, i.e. words start with
-s.title() uppercase characters, all remaining cased characters
- are lowercase.
-s.translate(table return a copy of s mapped through translation table (12)
-[,deletechars]) table.
-s.upper() return a copy of s converted to uppercase.
-s.zfill(width) return a string padded with zeroes on the left side and
- sliding a minus sign left if necessary. never truncates.
-
-Notes :
- (1) Padding is done using spaces.
- (2) If optional argument start is supplied, substring s[start:] is
-processed. If optional arguments start and end are supplied, substring s[start:
-end] is processed.
- (3) Optional argument errors may be given to set a different error handling
-scheme. The default for errors is 'strict', meaning that encoding errors raise
-a ValueError. Other possible values are 'ignore' and 'replace'.
- (4) If optional argument tabsize is not given, a tab size of 8 characters
-is assumed.
- (5) Returns false if string s does not contain at least one character.
- (6) Returns false if string s does not contain at least one cased
-character.
- (7) A titlecased string is a string in which uppercase characters may only
-follow uncased characters and lowercase characters only cased ones.
- (8) s is returned if width is less than len(s).
- (9) If the optional argument maxsplit is given, only the first maxsplit
-occurrences are replaced.
- (10) If sep is not specified or None, any whitespace string is a separator.
-If maxsplit is given, at most maxsplit splits are done.
- (11) Line breaks are not included in the resulting list unless keepends is
-given and true.
- (12) table must be a string of length 256. All characters occurring in the
-optional argument deletechars are removed prior to translation.
-
-String formatting with the % operator
-
-formatString % args--> evaluates to a string
-
- * formatString uses C printf format codes : %, c, s, i, d, u, o, x, X, e, E,
- f, g, G, r (details below).
- * Width and precision may be a * to specify that an integer argument gives
- the actual width or precision.
- * The flag characters -, +, blank, # and 0 are understood. (details below)
- * %s will convert any type argument to string (uses str() function)
- * args may be a single arg or a tuple of args
-
- '%s has %03d quote types.' % ('Python', 2) # => 'Python has 002 quote types.'
-
- * Right-hand-side can also be a mapping:
-
- a = '%(lang)s has %(c)03d quote types.' % {'c':2, 'lang':'Python}
-(vars() function very handy to use on right-hand-side.)
-
- Format codes
-Conversion Meaning
-d Signed integer decimal.
-i Signed integer decimal.
-o Unsigned octal.
-u Unsigned decimal.
-x Unsigned hexadecimal (lowercase).
-X Unsigned hexadecimal (uppercase).
-e Floating point exponential format (lowercase).
-E Floating point exponential format (uppercase).
-f Floating point decimal format.
-F Floating point decimal format.
-g Same as "e" if exponent is greater than -4 or less than precision,
- "f" otherwise.
-G Same as "E" if exponent is greater than -4 or less than precision,
- "F" otherwise.
-c Single character (accepts integer or single character string).
-r String (converts any python object using repr()).
-s String (converts any python object using str()).
-% No argument is converted, results in a "%" character in the result.
- (The complete specification is %%.)
-
- Conversion flag characters
-Flag Meaning
-# The value conversion will use the ``alternate form''.
-0 The conversion will be zero padded.
-- The converted value is left adjusted (overrides "-").
- (a space) A blank should be left before a positive number (or empty
- string) produced by a signed conversion.
-+ A sign character ("+" or "-") will precede the conversion (overrides a
- "space" flag).
-
-File Objects
-
-Created with built-in function open; may be created by other modules' functions
-as well.
-
-Operators on file objects
-
- File operations
- Operation Result
-f.close() Close file f.
-f.fileno() Get fileno (fd) for file f.
-f.flush() Flush file f's internal buffer.
-f.isatty() True if file f is connected to a tty-like dev, else False.
-f.read([size]) Read at most size bytes from file f and return as a string
- object. If size omitted, read to EOF.
-f.readline() Read one entire line from file f.
-f.readlines() Read until EOF with readline() and return list of lines read.
- Set file f's position, like "stdio's fseek()".
-f.seek(offset[, whence == 0 then use absolute indexing.
-whence=0]) whence == 1 then offset relative to current pos.
- whence == 2 then offset relative to file end.
-f.tell() Return file f's current position (byte offset).
-f.write(str) Write string to file f.
-f.writelines(list Write list of strings to file f.
-)
-
-File Exceptions
-
- EOFError
- End-of-file hit when reading (may be raised many times, e.g. if f is a
- tty).
- IOError
- Other I/O-related I/O operation failure.
- OSError
- OS system call failed.
-
-
- Advanced Types
-
- -See manuals for more details -
- + Module objects
- + Class objects
- + Class instance objects
- + Type objects (see module: types)
- + File objects (see above)
- + Slice objects
- + XRange objects
- + Callable types:
- o User-defined (written in Python):
- # User-defined Function objects
- # User-defined Method objects
- o Built-in (written in C):
- # Built-in Function objects
- # Built-in Method objects
- + Internal Types:
- o Code objects (byte-compile executable Python code: bytecode)
- o Frame objects (execution frames)
- o Traceback objects (stack trace of an exception)
-
-
- Statements
-
- pass -- Null statement
- del name[,name]* -- Unbind name(s) from object. Object will be indirectly
- (and automatically) deleted only if no longer referenced.
- print [>> fileobject,] [s1 [, s2 ]* [,]
- -- Writes to sys.stdout, or to fileobject if supplied.
- Puts spaces between arguments. Puts newline at end
- unless statement ends with comma.
- Print is not required when running interactively,
- simply typing an expression will print its value,
- unless the value is None.
- exec x [in globals [,locals]]
- -- Executes x in namespaces provided. Defaults
- to current namespaces. x can be a string, file
- object or a function object.
- callable(value,... [id=value], [*args], [**kw])
- -- Call function callable with parameters. Parameters can
- be passed by name or be omitted if function
- defines default values. E.g. if callable is defined as
- "def callable(p1=1, p2=2)"
- "callable()" <=> "callable(1, 2)"
- "callable(10)" <=> "callable(10, 2)"
- "callable(p2=99)" <=> "callable(1, 99)"
- *args is a tuple of positional arguments.
- **kw is a dictionary of keyword arguments.
-
- Assignment operators
-
- Caption
- Operator Result Notes
- a = b Basic assignment - assign object b to label a (1)
- a += b Roughly equivalent to a = a + b (2)
- a -= b Roughly equivalent to a = a - b (2)
- a *= b Roughly equivalent to a = a * b (2)
- a /= b Roughly equivalent to a = a / b (2)
- a %= b Roughly equivalent to a = a % b (2)
- a **= b Roughly equivalent to a = a ** b (2)
- a &= b Roughly equivalent to a = a & b (2)
- a |= b Roughly equivalent to a = a | b (2)
- a ^= b Roughly equivalent to a = a ^ b (2)
- a >>= b Roughly equivalent to a = a >> b (2)
- a <<= b Roughly equivalent to a = a << b (2)
-
- Notes :
- (1) Can unpack tuples, lists, and strings.
- first, second = a[0:2]; [f, s] = range(2); c1,c2,c3='abc'
- Tip: x,y = y,x swaps x and y.
- (2) Not exactly equivalent - a is evaluated only once. Also, where
- possible, operation performed in-place - a is modified rather than
- replaced.
-
- Control Flow
-
- if condition: suite
- [elif condition: suite]*
- [else: suite] -- usual if/else_if/else statement
- while condition: suite
- [else: suite]
- -- usual while statement. "else" suite is executed
- after loop exits, unless the loop is exited with
- "break"
- for element in sequence: suite
- [else: suite]
- -- iterates over sequence, assigning each element to element.
- Use built-in range function to iterate a number of times.
- "else" suite executed at end unless loop exited
- with "break"
- break -- immediately exits "for" or "while" loop
- continue -- immediately does next iteration of "for" or "while" loop
- return [result] -- Exits from function (or method) and returns result (use a tuple to
- return more than one value). If no result given, then returns None.
- yield result -- Freezes the execution frame of a generator and returns the result
- to the iterator's .__next__() method. Upon the next call to __next__(),
- resumes execution at the frozen point with all of the local variables
- still intact.
-
- Exception Statements
-
- assert expr[, message]
- -- expr is evaluated. if false, raises exception AssertionError
- with message. Inhibited if __debug__ is 0.
- try: suite1
- [except [exception [, value]: suite2]+
- [else: suite3]
- -- statements in suite1 are executed. If an exception occurs, look
- in "except" clauses for matching <exception>. If matches or bare
- "except" execute suite of that clause. If no exception happens
- suite in "else" clause is executed after suite1.
- If exception has a value, it is put in value.
- exception can also be tuple of exceptions, e.g.
- "except (KeyError, NameError), val: print val"
- try: suite1
- finally: suite2
- -- statements in suite1 are executed. If no
- exception, execute suite2 (even if suite1 is
- exited with a "return", "break" or "continue"
- statement). If exception did occur, executes
- suite2 and then immediately reraises exception.
- raise exception [,value [, traceback]]
- -- raises exception with optional value
- value. Arg traceback specifies a traceback object to
- use when printing the exception's backtrace.
- raise -- a raise statement without arguments re-raises
- the last exception raised in the current function
-An exception is either a string (object) or a class instance.
- Can create a new one simply by creating a new string:
-
- my_exception = 'You did something wrong'
- try:
- if bad:
- raise my_exception, bad
- except my_exception, value:
- print 'Oops', value
-
-Exception classes must be derived from the predefined class: Exception, e.g.:
- class text_exception(Exception): pass
- try:
- if bad:
- raise text_exception()
- # This is a shorthand for the form
- # "raise <class>, <instance>"
- except Exception:
- print 'Oops'
- # This will be printed because
- # text_exception is a subclass of Exception
-When an error message is printed for an unhandled exception which is a
-class, the class name is printed, then a colon and a space, and
-finally the instance converted to a string using the built-in function
-str().
-All built-in exception classes derives from Exception, itself
-derived from BaseException.
-
-Name Space Statements
-
-[1.51: On Mac & Windows, the case of module file names must now match the case
-as used
- in the import statement]
-Packages (>1.5): a package is a name space which maps to a directory including
- module(s) and the special initialization module '__init__.py'
- (possibly empty). Packages/dirs can be nested. You address a
- module's symbol via '[package.[package...]module.symbol's.
-import module1 [as name1] [, module2]*
- -- imports modules. Members of module must be
- referred to by qualifying with [package.]module name:
- "import sys; print sys.argv:"
- "import package1.subpackage.module; package1.subpackage.module.foo()"
- module1 renamed as name1, if supplied.
-from module import name1 [as othername1] [, name2]*
- -- imports names from module module in current namespace.
- "from sys import argv; print argv"
- "from package1 import module; module.foo()"
- "from package1.module import foo; foo()"
- name1 renamed as othername1, if supplied.
-from module import *
- -- imports all names in module, except those starting with "_";
- *to be used sparsely, beware of name clashes* :
- "from sys import *; print argv"
- "from package.module import *; print x'
- NB: "from package import *" only imports the symbols defined
- in the package's __init__.py file, not those in the
- template modules!
-global name1 [, name2]*
- -- names are from global scope (usually meaning from module)
- rather than local (usually meaning only in function).
- -- E.g. in fct without "global" statements, assuming
- "a" is name that hasn't been used in fct or module
- so far:
- -Try to read from "a" -> NameError
- -Try to write to "a" -> creates "a" local to fcn
- -If "a" not defined in fct, but is in module, then
- -Try to read from "a", gets value from module
- -Try to write to "a", creates "a" local to fct
- But note "a[0]=3" starts with search for "a",
- will use to global "a" if no local "a".
-
-Function Definition
-
-def func_id ([param_list]): suite
- -- Creates a function object & binds it to name func_id.
-
- param_list ::= [id [, id]*]
- id ::= value | id = value | *id | **id
- [Args are passed by value.Thus only args representing a mutable object
- can be modified (are inout parameters). Use a tuple to return more than
- one value]
-
-Example:
- def test (p1, p2 = 1+1, *rest, **keywords):
- -- Parameters with "=" have default value (v is
- evaluated when function defined).
- If list has "*id" then id is assigned a tuple of
- all remaining args passed to function (like C vararg)
- If list has "**id" then id is assigned a dictionary of
- all extra arguments passed as keywords.
-
-Class Definition
-
-class <class_id> [(<super_class1> [,<super_class2>]*)]: <suite>
- -- Creates a class object and assigns it name <class_id>
- <suite> may contain local "defs" of class methods and
- assignments to class attributes.
-Example:
- class my_class (class1, class_list[3]): ...
- Creates a class object inheriting from both "class1" and whatever
- class object "class_list[3]" evaluates to. Assigns new
- class object to name "my_class".
- - First arg to class methods is always instance object, called 'self'
- by convention.
- - Special method __init__() is called when instance is created.
- - Special method __del__() called when no more reference to object.
- - Create instance by "calling" class object, possibly with arg
- (thus instance=apply(aClassObject, args...) creates an instance!)
- - In current implementation, can't subclass off built-in
- classes. But can "wrap" them, see UserDict & UserList modules,
- and see __getattr__() below.
-Example:
- class c (c_parent):
- def __init__(self, name): self.name = name
- def print_name(self): print "I'm", self.name
- def call_parent(self): c_parent.print_name(self)
- instance = c('tom')
- print instance.name
- 'tom'
- instance.print_name()
- "I'm tom"
- Call parent's super class by accessing parent's method
- directly and passing "self" explicitly (see "call_parent"
- in example above).
- Many other special methods available for implementing
- arithmetic operators, sequence, mapping indexing, etc.
-
-Documentation Strings
-
-Modules, classes and functions may be documented by placing a string literal by
-itself as the first statement in the suite. The documentation can be retrieved
-by getting the '__doc__' attribute from the module, class or function.
-Example:
- class C:
- "A description of C"
- def __init__(self):
- "A description of the constructor"
- # etc.
-Then c.__doc__ == "A description of C".
-Then c.__init__.__doc__ == "A description of the constructor".
-
-Others
-
-lambda [param_list]: returnedExpr
- -- Creates an anonymous function. returnedExpr must be
- an expression, not a statement (e.g., not "if xx:...",
- "print xxx", etc.) and thus can't contain newlines.
- Used mostly for filter(), map() functions, and GUI callbacks..
-List comprehensions
-result = [expression for item1 in sequence1 [if condition1]
- [for item2 in sequence2 ... for itemN in sequenceN]
- ]
-is equivalent to:
-result = []
-for item1 in sequence1:
- for item2 in sequence2:
- ...
- for itemN in sequenceN:
- if (condition1) and furthur conditions:
- result.append(expression)
-
-
-
-Built-In Functions
-
- Built-In Functions
- Function Result
-__import__(name[, Imports module within the given context (see lib ref for
-globals[, locals[, more details)
-fromlist]]])
-abs(x) Return the absolute value of number x.
-bool(x) Returns True when the argument x is true and False otherwise.
-buffer(obj) Creates a buffer reference to an object.
-chr(i) Returns one-character string whose ASCII code isinteger i
-classmethod(f) Converts a function f, into a method with the class as the
- first argument. Useful for creating alternative constructors.
-cmp(x,y) Returns negative, 0, positive if x <, ==, > to y
-compile(string, from which the code was read, or eg. '<string>'if not read
-filename, kind) from file.kind can be 'eval' if string is a single stmt, or
- 'single' which prints the output of expression statements
- that evaluate to something else than None, or be 'exec'.
-complex(real[, Builds a complex object (can also be done using J or j
-image]) suffix,e.g. 1+3J)
-delattr(obj, name) deletes attribute named name of object obj <=> del obj.name
- If no args, returns the list of names in current
-dict([items]) Create a new dictionary from the specified item list.
-dir([object]) local symbol table. With a module, class or class
- instance object as arg, returns list of names in its attr.
- dict.
-divmod(a,b) Returns tuple of (a/b, a%b)
-enumerate(seq) Return a iterator giving: (0, seq[0]), (1, seq[1]), ...
-eval(s[, globals[, Eval string s in (optional) globals, locals contexts.s must
-locals]]) have no NUL's or newlines. s can also be acode object.
- Example: x = 1; incr_x = eval('x + 1')
-filter(function, Constructs a list from those elements of sequence for which
-sequence) function returns true. function takes one parameter.
-float(x) Converts a number or a string to floating point.
-getattr(object, [<default> arg added in 1.5.2]Gets attribute called name
-name[, default])) from object,e.g. getattr(x, 'f') <=> x.f). If not found,
- raises AttributeError or returns default if specified.
-globals() Returns a dictionary containing current global variables.
-hasattr(object, Returns true if object has attr called name.
-name)
-hash(object) Returns the hash value of the object (if it has one)
-help(f) Display documentation on object f.
-hex(x) Converts a number x to a hexadecimal string.
-id(object) Returns a unique 'identity' integer for an object.
-int(x[, base]) base paramenter specifies base from which to convert string
- values.
-isinstance(obj, Returns true if obj is an instance of class. Ifissubclass
-class) (A,B) then isinstance(x,A) => isinstance(x,B)
-issubclass(class1, returns true if class1 is derived from class2
-class2)
- Returns the length (the number of items) of an object
-iter(collection) Returns an iterator over the collection.
-len(obj) (sequence, dictionary, or instance of class implementing
- __len__).
-list(sequence) Converts sequence into a list. If already a list,returns a
- copy of it.
-locals() Returns a dictionary containing current local variables.
- Applies function to every item of list and returns a listof
-map(function, list, the results. If additional arguments are passed,function
-...) must take that many arguments and it is givento function on
- each call.
-max(seq) Returns the largest item of the non-empty sequence seq.
-min(seq) Returns the smallest item of a non-empty sequence seq.
-oct(x) Converts a number to an octal string.
-open(filename [, Returns a new file object. First two args are same asthose
-mode='r', [bufsize= for C's "stdio open" function. bufsize is 0for unbuffered,
-implementation 1 for line-buffered, negative forsys-default, all else, of
-dependent]]) (about) given size.
-ord(c) Returns integer ASCII value of c (a string of len 1). Works
- with Unicode char.
-object() Create a base type. Used as a superclass for new-style objects.
-open(name Open a file.
- [, mode
- [, buffering]])
-pow(x, y [, z]) Returns x to power y [modulo z]. See also ** operator.
-property() Created a property with access controlled by functions.
-range(start [,end Returns list of ints from >= start and < end. With 1 arg,
-[, step]]) list from 0..arg-1. With 2 args, list from start..end-1.
- With 3 args, list from start up to end by step
- after fixing it.
-repr(object) Returns a string containing a printable and if possible
- evaluable representation of an object.
- Class redefinable (__repr__). See also str().
-round(x, n=0) Returns the floating point value x rounded to n digitsafter
- the decimal point.
-setattr(object, This is the counterpart of getattr(). setattr(o, 'foobar',
-name, value) 3) <=> o.foobar = 3. Creates attribute if it doesn't exist!
-slice([start,] stop Returns a slice object representing a range, with R/
-[, step]) O attributes: start, stop, step.
-staticmethod() Convert a function to method with no self or class
- argument. Useful for methods associated with a class that
- do not need access to an object's internal state.
-str(object) Returns a string containing a nicely
- printable representation of an object. Class overridable
- (__str__).See also repr().
-super(type) Create an unbound super object. Used to call cooperative
- superclass methods.
-sum(sequence, Add the values in the sequence and return the sum.
- [start])
-tuple(sequence) Creates a tuple with same elements as sequence. If already
- a tuple, return itself (not a copy).
- Returns a type object [see module types] representing
- thetype of obj. Example: import typesif type(x) ==
-type(obj) types.StringType: print 'It is a string'NB: it is
- recommanded to use the following form:if isinstance(x,
- types.StringType): etc...
-unichr(code) code.
-unicode(string[, Creates a Unicode string from a 8-bit string, using
-encoding[, error thegiven encoding name and error treatment ('strict',
-]]]) 'ignore',or 'replace'}.
- Without arguments, returns a dictionary correspondingto the
- current local symbol table. With a module,class or class
-vars([object]) instance object as argumentreturns a dictionary
- corresponding to the object'ssymbol table. Useful with "%"
- formatting operator.
-zip(seq1[, seq2, Returns an iterator of tuples where each tuple contains
-...]) the nth element of each of the argument sequences.
-
-
-
-Built-In Exceptions
-
-Exception>
- Root class for all exceptions
- SystemExit
- On 'sys.exit()'
- StopIteration
- Signal the end from iterator.__next__()
- ArithmeticError
- Base class for OverflowError, ZeroDivisionError,
- FloatingPointError
- FloatingPointError
- When a floating point operation fails.
- OverflowError
- On excessively large arithmetic operation
- ZeroDivisionError
- On division or modulo operation with 0 as 2nd arg
- AssertionError
- When an assert statement fails.
- AttributeError
- On attribute reference or assignment failure
- EnvironmentError [new in 1.5.2]
- On error outside Python; error arg tuple is (errno, errMsg...)
- IOError [changed in 1.5.2]
- I/O-related operation failure
- OSError [new in 1.5.2]
- used by the os module's os.error exception.
- EOFError
- Immediate end-of-file hit by input() or raw_input()
- ImportError
- On failure of `import' to find module or name
- KeyboardInterrupt
- On user entry of the interrupt key (often `Control-C')
- LookupError
- base class for IndexError, KeyError
- IndexError
- On out-of-range sequence subscript
- KeyError
- On reference to a non-existent mapping (dict) key
- MemoryError
- On recoverable memory exhaustion
- NameError
- On failure to find a local or global (unqualified) name
- RuntimeError
- Obsolete catch-all; define a suitable error instead
- NotImplementedError [new in 1.5.2]
- On method not implemented
- SyntaxError
- On parser encountering a syntax error
- IndentationError
- On parser encountering an indentation syntax error
- TabError
- On parser encountering an indentation syntax error
- SystemError
- On non-fatal interpreter error - bug - report it
- TypeError
- On passing inappropriate type to built-in op or func
- ValueError
- On arg error not covered by TypeError or more precise
- Warning
- UserWarning
- DeprecationWarning
- PendingDeprecationWarning
- SyntaxWarning
- RuntimeWarning
- FutureWarning
-
-
-
-Standard methods & operators redefinition in classes
-
-Standard methods & operators map to special '__methods__' and thus may be
- redefined (mostly in user-defined classes), e.g.:
- class x:
- def __init__(self, v): self.value = v
- def __add__(self, r): return self.value + r
- a = x(3) # sort of like calling x.__init__(a, 3)
- a + 4 # is equivalent to a.__add__(4)
-
-Special methods for any class
-
-(s: self, o: other)
- __init__(s, args) instance initialization (on construction)
- __del__(s) called on object demise (refcount becomes 0)
- __repr__(s) repr() and `...` conversions
- __str__(s) str() and 'print' statement
- __cmp__(s, o) Compares s to o and returns <0, 0, or >0.
- Implements >, <, == etc...
- __hash__(s) Compute a 32 bit hash code; hash() and dictionary ops
- __bool__(s) Returns False or True for truth value testing
- __getattr__(s, name) called when attr lookup doesn't find <name>
- __setattr__(s, name, val) called when setting an attr
- (inside, don't use "self.name = value"
- use "self.__dict__[name] = val")
- __delattr__(s, name) called to delete attr <name>
- __call__(self, *args) called when an instance is called as function.
-
-Operators
-
- See list in the operator module. Operator function names are provided with
- 2 variants, with or without
- ading & trailing '__' (eg. __add__ or add).
-
- Numeric operations special methods
- (s: self, o: other)
-
- s+o = __add__(s,o) s-o = __sub__(s,o)
- s*o = __mul__(s,o) s/o = __div__(s,o)
- s%o = __mod__(s,o) divmod(s,o) = __divmod__(s,o)
- s**o = __pow__(s,o)
- s&o = __and__(s,o)
- s^o = __xor__(s,o) s|o = __or__(s,o)
- s<<o = __lshift__(s,o) s>>o = __rshift__(s,o)
- bool(s) = __bool__(s) (used in boolean testing)
- -s = __neg__(s) +s = __pos__(s)
- abs(s) = __abs__(s) ~s = __invert__(s) (bitwise)
- s+=o = __iadd__(s,o) s-=o = __isub__(s,o)
- s*=o = __imul__(s,o) s/=o = __idiv__(s,o)
- s%=o = __imod__(s,o)
- s**=o = __ipow__(s,o)
- s&=o = __iand__(s,o)
- s^=o = __ixor__(s,o) s|=o = __ior__(s,o)
- s<<=o = __ilshift__(s,o) s>>=o = __irshift__(s,o)
- Conversions
- int(s) = __int__(s)
- float(s) = __float__(s) complex(s) = __complex__(s)
- oct(s) = __oct__(s) hex(s) = __hex__(s)
- Right-hand-side equivalents for all binary operators exist;
- are called when class instance is on r-h-s of operator:
- a + 3 calls __add__(a, 3)
- 3 + a calls __radd__(a, 3)
-
- All seqs and maps, general operations plus:
- (s: self, i: index or key)
-
- len(s) = __len__(s) length of object, >= 0. Length 0 == false
- s[i] = __getitem__(s,i) Element at index/key i, origin 0
-
- Sequences, general methods, plus:
- s[i]=v = __setitem__(s,i,v)
- del s[i] = __delitem__(s,i)
- s[i:j] = __getslice__(s,i,j)
- s[i:j]=seq = __setslice__(s,i,j,seq)
- del s[i:j] = __delslice__(s,i,j) == s[i:j] = []
- seq * n = __repeat__(seq, n)
- s1 + s2 = __concat__(s1, s2)
- i in s = __contains__(s, i)
- Mappings, general methods, plus
- hash(s) = __hash__(s) - hash value for dictionary references
- s[k]=v = __setitem__(s,k,v)
- del s[k] = __delitem__(s,k)
-
-Special informative state attributes for some types:
-
- Modules:
- __doc__ (string/None, R/O): doc string (<=> __dict__['__doc__'])
- __name__(string, R/O): module name (also in __dict__['__name__'])
- __dict__ (dict, R/O): module's name space
- __file__(string/undefined, R/O): pathname of .pyc, .pyo or .pyd (undef for
- modules statically linked to the interpreter)
-
- Classes: [in bold: writable since 1.5.2]
- __doc__ (string/None, R/W): doc string (<=> __dict__['__doc__'])
- __module__ is the module name in which the class was defined
- __name__(string, R/W): class name (also in __dict__['__name__'])
- __bases__ (tuple, R/W): parent classes
- __dict__ (dict, R/W): attributes (class name space)
-
- Instances:
- __class__ (class, R/W): instance's class
- __dict__ (dict, R/W): attributes
-
- User-defined functions: [bold: writable since 1.5.2]
- __doc__ (string/None, R/W): doc string
- __name__(string, R/O): function name
- func_doc (R/W): same as __doc__
- func_name (R/O): same as __name__
- func_defaults (tuple/None, R/W): default args values if any
- func_code (code, R/W): code object representing the compiled function body
- func_globals (dict, R/O): ref to dictionary of func global variables
- func_dict (dict, R/W): same as __dict__ contains the namespace supporting
- arbitrary function attributes
- func_closure (R/O): None or a tuple of cells that contain bindings
- for the function's free variables.
-
-
- User-defined Methods:
- __doc__ (string/None, R/O): doc string
- __name__(string, R/O): method name (same as im_func.__name__)
- im_class (class, R/O): class defining the method (may be a base class)
- im_self (instance/None, R/O): target instance object (None if unbound)
- im_func (function, R/O): function object
-
- Built-in Functions & methods:
- __doc__ (string/None, R/O): doc string
- __name__ (string, R/O): function name
- __self__ : [methods only] target object
-
- Codes:
- co_name (string, R/O): function name
- co_argcount (int, R/0): number of positional args
- co_nlocals (int, R/O): number of local vars (including args)
- co_varnames (tuple, R/O): names of local vars (starting with args)
- co_cellvars (tuple, R/O)) the names of local variables referenced by
- nested functions
- co_freevars (tuple, R/O)) names of free variables
- co_code (string, R/O): sequence of bytecode instructions
- co_consts (tuple, R/O): litterals used by the bytecode, 1st one is
- fct doc (or None)
- co_names (tuple, R/O): names used by the bytecode
- co_filename (string, R/O): filename from which the code was compiled
- co_firstlineno (int, R/O): first line number of the function
- co_lnotab (string, R/O): string encoding bytecode offsets to line numbers.
- co_stacksize (int, R/O): required stack size (including local vars)
- co_flags (int, R/O): flags for the interpreter
- bit 2 set if fct uses "*arg" syntax
- bit 3 set if fct uses '**keywords' syntax
- Frames:
- f_back (frame/None, R/O): previous stack frame (toward the caller)
- f_code (code, R/O): code object being executed in this frame
- f_locals (dict, R/O): local vars
- f_globals (dict, R/O): global vars
- f_builtins (dict, R/O): built-in (intrinsic) names
- f_restricted (int, R/O): flag indicating whether fct is executed in
- restricted mode
- f_lineno (int, R/O): current line number
- f_lasti (int, R/O): precise instruction (index into bytecode)
- f_trace (function/None, R/W): debug hook called at start of each source line
- Tracebacks:
- tb_next (frame/None, R/O): next level in stack trace (toward the frame where
- the exception occurred)
- tb_frame (frame, R/O): execution frame of the current level
- tb_lineno (int, R/O): line number where the exception occurred
- tb_lasti (int, R/O): precise instruction (index into bytecode)
-
- Slices:
- start (any/None, R/O): lowerbound
- stop (any/None, R/O): upperbound
- step (any/None, R/O): step value
-
- Complex numbers:
- real (float, R/O): real part
- imag (float, R/O): imaginary part
-
-
-Important Modules
-
- sys
-
- Some sys variables
- Variable Content
-argv The list of command line arguments passed to aPython
- script. sys.argv[0] is the script name.
-builtin_module_names A list of strings giving the names of all moduleswritten
- in C that are linked into this interpreter.
-check_interval How often to check for thread switches or signals(measured
- in number of virtual machine instructions)
-last_type, Set only when an exception not handled andinterpreter
-last_value, prints an error. Used by debuggers.
-last_traceback
-maxint maximum positive value for integers
-modules Dictionary of modules that have already been loaded.
-path Search path for external modules. Can be modifiedby
- program. sys.path[0] == dir of script executing
-platform The current platform, e.g. "sunos5", "win32"
-ps1, ps2 prompts to use in interactive mode.
- File objects used for I/O. One can redirect byassigning a
-stdin, stdout, new file object to them (or any object:.with a method
-stderr write(string) for stdout/stderr,.with a method readline()
- for stdin)
-version string containing version info about Python interpreter.
- (and also: copyright, dllhandle, exec_prefix, prefix)
-version_info tuple containing Python version info - (major, minor,
- micro, level, serial).
-
- Some sys functions
- Function Result
-exit(n) Exits with status n. Raises SystemExit exception.(Hence can
- be caught and ignored by program)
-getrefcount(object Returns the reference count of the object. Generally one
-) higher than you might expect, because of object arg temp
- reference.
-setcheckinterval( Sets the interpreter's thread switching interval (in number
-interval) of virtual code instructions, default:100).
-settrace(func) Sets a trace function: called before each line ofcode is
- exited.
-setprofile(func) Sets a profile function for performance profiling.
- Info on exception currently being handled; this is atuple
- (exc_type, exc_value, exc_traceback).Warning: assigning the
-exc_info() traceback return value to a local variable in a
- function handling an exception will cause a circular
- reference.
-getrecursionlimit Retrieve maximum recursion depth.
-()
-setrecursionlimit Set maximum recursion depth. (Defaults to 1000.)
-()
-
-
-
- os
-"synonym" for whatever O/S-specific module is proper for current environment.
-this module uses posix whenever possible.
-(see also M.A. Lemburg's utility http://www.lemburg.com/files/python/
-platform.py)
-
- Some os variables
- Variable Meaning
-name name of O/S-specific module (e.g. "posix", "mac", "nt")
-path O/S-specific module for path manipulations.
- On Unix, os.path.split() <=> posixpath.split()
-curdir string used to represent current directory ('.')
-pardir string used to represent parent directory ('..')
-sep string used to separate directories ('/' or '\'). Tip: use
- os.path.join() to build portable paths.
-altsep Alternate sep
-if applicable (None
-otherwise)
-pathsep character used to separate search path components (as in
- $PATH), eg. ';' for windows.
-linesep line separator as used in binary files, ie '\n' on Unix, '\
- r\n' on Dos/Win, '\r'
-
- Some os functions
- Function Result
-makedirs(path[, Recursive directory creation (create required intermediary
-mode=0777]) dirs); os.error if fails.
-removedirs(path) Recursive directory delete (delete intermediary empty
- dirs); if fails.
-renames(old, new) Recursive directory or file renaming; os.error if fails.
-
-
-
- posix
-don't import this module directly, import os instead !
-(see also module: shutil for file copy & remove fcts)
-
- posix Variables
-Variable Meaning
-environ dictionary of environment variables, e.g.posix.environ['HOME'].
-error exception raised on POSIX-related error.
- Corresponding value is tuple of errno code and perror() string.
-
- Some posix functions
- Function Result
-chdir(path) Changes current directory to path.
-chmod(path, Changes the mode of path to the numeric mode
-mode)
-close(fd) Closes file descriptor fd opened with posix.open.
-_exit(n) Immediate exit, with no cleanups, no SystemExit,etc. Should use
- this to exit a child process.
-execv(p, args) "Become" executable p with args args
-getcwd() Returns a string representing the current working directory
-getpid() Returns the current process id
-fork() Like C's fork(). Returns 0 to child, child pid to parent.[Not
- on Windows]
-kill(pid, Like C's kill [Not on Windows]
-signal)
-listdir(path) Lists (base)names of entries in directory path, excluding '.'
- and '..'
-lseek(fd, pos, Sets current position in file fd to position pos, expressedas
-how) an offset relative to beginning of file (how=0), tocurrent
- position (how=1), or to end of file (how=2)
-mkdir(path[, Creates a directory named path with numeric mode (default 0777)
-mode])
-open(file, Like C's open(). Returns file descriptor. Use file object
-flags, mode) fctsrather than this low level ones.
-pipe() Creates a pipe. Returns pair of file descriptors (r, w) [Not on
- Windows].
-popen(command, Opens a pipe to or from command. Result is a file object to
-mode='r', read to orwrite from, as indicated by mode being 'r' or 'w'.
-bufSize=0) Use it to catch acommand output ('r' mode) or to feed it ('w'
- mode).
-remove(path) See unlink.
-rename(src, dst Renames/moves the file or directory src to dst. [error iftarget
-) name already exists]
-rmdir(path) Removes the empty directory path
-read(fd, n) Reads n bytes from file descriptor fd and return as string.
- Returns st_mode, st_ino, st_dev, st_nlink, st_uid,st_gid,
-stat(path) st_size, st_atime, st_mtime, st_ctime.[st_ino, st_uid, st_gid
- are dummy on Windows]
-system(command) Executes string command in a subshell. Returns exitstatus of
- subshell (usually 0 means OK).
- Returns accumulated CPU times in sec (user, system, children's
-times() user,children's sys, elapsed real time). [3 last not on
- Windows]
-unlink(path) Unlinks ("deletes") the file (not dir!) path. same as: remove
-utime(path, ( Sets the access & modified time of the file to the given tuple
-aTime, mTime)) of values.
-wait() Waits for child process completion. Returns tuple ofpid,
- exit_status [Not on Windows]
-waitpid(pid, Waits for process pid to complete. Returns tuple ofpid,
-options) exit_status [Not on Windows]
-write(fd, str) Writes str to file fd. Returns nb of bytes written.
-
-
-
- posixpath
-Do not import this module directly, import os instead and refer to this module
-as os.path. (e.g. os.path.exists(p)) !
-
- Some posixpath functions
- Function Result
-abspath(p) Returns absolute path for path p, taking current working dir in
- account.
-dirname/
-basename(p directory and name parts of the path p. See also split.
-)
-exists(p) True if string p is an existing path (file or directory)
-expanduser Returns string that is (a copy of) p with "~" expansion done.
-(p)
-expandvars Returns string that is (a copy of) p with environment vars expanded.
-(p) [Windows: case significant; must use Unix: $var notation, not %var%]
-getsize( return the size in bytes of filename. raise os.error.
-filename)
-getmtime( return last modification time of filename (integer nb of seconds
-filename) since epoch).
-getatime( return last access time of filename (integer nb of seconds since
-filename) epoch).
-isabs(p) True if string p is an absolute path.
-isdir(p) True if string p is a directory.
-islink(p) True if string p is a symbolic link.
-ismount(p) True if string p is a mount point [true for all dirs on Windows].
-join(p[,q Joins one or more path components intelligently.
-[,...]])
- Splits p into (head, tail) where tail is lastpathname component and
-split(p) <head> is everything leadingup to that. <=> (dirname(p), basename
- (p))
-splitdrive Splits path p in a pair ('drive:', tail) [Windows]
-(p)
-splitext(p Splits into (root, ext) where last comp of root contains no periods
-) and ext is empty or startswith a period.
- Calls the function visit with arguments(arg, dirname, names) for
- each directory recursively inthe directory tree rooted at p
-walk(p, (including p itself if it's a dir)The argument dirname specifies the
-visit, arg visited directory, the argumentnames lists the files in the
-) directory. The visit function maymodify names to influence the set
- of directories visited belowdirname, e.g., to avoid visiting certain
- parts of the tree.
-
-
-
- shutil
-high-level file operations (copying, deleting).
-
- Main shutil functions
- Function Result
-copy(src, dst) Copies the contents of file src to file dst, retaining file
- permissions.
-copytree(src, dst Recursively copies an entire directory tree rooted at src
-[, symlinks]) into dst (which should not already exist). If symlinks is
- true, links insrc are kept as such in dst.
-rmtree(path[, Deletes an entire directory tree, ignoring errors if
-ignore_errors[, ignore_errors true,or calling onerror(func, path,
-onerror]]) sys.exc_info()) if supplied with
-
-(and also: copyfile, copymode, copystat, copy2)
-
-time
-
- Variables
-Variable Meaning
-altzone signed offset of local DST timezone in sec west of the 0th meridian.
-daylight nonzero if a DST timezone is specified
-
- Functions
- Function Result
-time() return a float representing UTC time in seconds since the epoch.
-gmtime(secs), return a tuple representing time : (year aaaa, month(1-12),day
-localtime( (1-31), hour(0-23), minute(0-59), second(0-59), weekday(0-6, 0 is
-secs) monday), Julian day(1-366), daylight flag(-1,0 or 1))
-asctime(
-timeTuple),
-strftime(
-format, return a formatted string representing time.
-timeTuple)
-mktime(tuple) inverse of localtime(). Return a float.
-strptime( parse a formatted string representing time, return tuple as in
-string[, gmtime().
-format])
-sleep(secs) Suspend execution for <secs> seconds. <secs> can be a float.
-
-and also: clock, ctime.
-
- string
-
-As of Python 2.0, much (though not all) of the functionality provided by the
-string module have been superseded by built-in string methods - see Operations
-on strings for details.
-
- Some string variables
- Variable Meaning
-digits The string '0123456789'
-hexdigits, octdigits legal hexadecimal & octal digits
-letters, uppercase, lowercase, Strings containing the appropriate
-whitespace characters
-index_error Exception raised by index() if substr not
- found.
-
- Some string functions
- Function Result
-expandtabs(s, returns a copy of string <s> with tabs expanded.
-tabSize)
-find/rfind(s, sub Return the lowest/highest index in <s> where the substring
-[, start=0[, end= <sub> is found such that <sub> is wholly contained ins
-0]) [start:end]. Return -1 if <sub> not found.
-ljust/rjust/center Return a copy of string <s> left/right justified/centerd in
-(s, width) afield of given width, padded with spaces. <s> is
- nevertruncated.
-lower/upper(s) Return a string that is (a copy of) <s> in lowercase/
- uppercase
-split(s[, sep= Return a list containing the words of the string <s>,using
-whitespace[, the string <sep> as a separator.
-maxsplit=0]])
-join(words[, sep=' Concatenate a list or tuple of words with
-']) interveningseparators; inverse of split.
-replace(s, old, Returns a copy of string <s> with all occurrences of
-new[, maxsplit=0] substring<old> replaced by <new>. Limits to <maxsplit>
- firstsubstitutions if specified.
-strip(s) Return a string that is (a copy of) <s> without leadingand
- trailing whitespace. see also lstrip, rstrip.
-
-
-
- re (sre)
-
-Handles Unicode strings. Implemented in new module sre, re now a mere front-end
-for compatibility.
-Patterns are specified as strings. Tip: Use raw strings (e.g. r'\w*') to
-litteralize backslashes.
-
-
- Regular expression syntax
- Form Description
-. matches any character (including newline if DOTALL flag specified)
-^ matches start of the string (of every line in MULTILINE mode)
-$ matches end of the string (of every line in MULTILINE mode)
-* 0 or more of preceding regular expression (as many as possible)
-+ 1 or more of preceding regular expression (as many as possible)
-? 0 or 1 occurrence of preceding regular expression
-*?, +?, ?? Same as *, + and ? but matches as few characters as possible
-{m,n} matches from m to n repetitions of preceding RE
-{m,n}? idem, attempting to match as few repetitions as possible
-[ ] defines character set: e.g. '[a-zA-Z]' to match all letters(see also
- \w \S)
-[^ ] defines complemented character set: matches if char is NOT in set
- escapes special chars '*?+&$|()' and introduces special sequences
-\ (see below). Due to Python string rules, write as '\\' orr'\' in the
- pattern string.
-\\ matches a litteral '\'; due to Python string rules, write as '\\\\
- 'in pattern string, or better using raw string: r'\\'.
-| specifies alternative: 'foo|bar' matches 'foo' or 'bar'
-(...) matches any RE inside (), and delimits a group.
-(?:...) idem but doesn't delimit a group.
- matches if ... matches next, but doesn't consume any of the string
-(?=...) e.g. 'Isaac (?=Asimov)' matches 'Isaac' only if followed by
- 'Asimov'.
-(?!...) matches if ... doesn't match next. Negative of (?=...)
-(?P<name matches any RE inside (), and delimits a named group. (e.g. r'(?P
->...) <id>[a-zA-Z_]\w*)' defines a group named id)
-(?P=name) matches whatever text was matched by the earlier group named name.
-(?#...) A comment; ignored.
-(?letter) letter is one of 'i','L', 'm', 's', 'x'. Set the corresponding flags
- (re.I, re.L, re.M, re.S, re.X) for the entire RE.
-
- Special sequences
-Sequence Description
-number matches content of the group of the same number; groups are numbered
- starting from 1
-\A matches only at the start of the string
-\b empty str at beg or end of word: '\bis\b' matches 'is', but not 'his'
-\B empty str NOT at beginning or end of word
-\d any decimal digit (<=> [0-9])
-\D any non-decimal digit char (<=> [^O-9])
-\s any whitespace char (<=> [ \t\n\r\f\v])
-\S any non-whitespace char (<=> [^ \t\n\r\f\v])
-\w any alphaNumeric char (depends on LOCALE flag)
-\W any non-alphaNumeric char (depends on LOCALE flag)
-\Z matches only at the end of the string
-
- Variables
-Variable Meaning
-error Exception when pattern string isn't a valid regexp.
-
- Functions
- Function Result
- Compile a RE pattern string into a regular expression object.
- Flags (combinable by |):
-
- I or IGNORECASE or (?i)
- case insensitive matching
-compile( L or LOCALE or (?L)
-pattern[, make \w, \W, \b, \B dependent on thecurrent locale
-flags=0]) M or MULTILINE or (?m)
- matches every new line and not onlystart/end of the whole
- string
- S or DOTALL or (?s)
- '.' matches ALL chars, including newline
- X or VERBOSE or (?x)
- Ignores whitespace outside character sets
-escape(string) return (a copy of) string with all non-alphanumerics
- backslashed.
-match(pattern, if 0 or more chars at beginning of <string> match the RE pattern
-string[, flags string,return a corresponding MatchObject instance, or None if
-]) no match.
-search(pattern scan thru <string> for a location matching <pattern>, return
-, string[, acorresponding MatchObject instance, or None if no match.
-flags])
-split(pattern, split <string> by occurrences of <pattern>. If capturing () are
-string[, used inpattern, then occurrences of patterns or subpatterns are
-maxsplit=0]) also returned.
-findall( return a list of non-overlapping matches in <pattern>, either a
-pattern, list ofgroups or a list of tuples if the pattern has more than 1
-string) group.
- return string obtained by replacing the (<count> first) lefmost
-sub(pattern, non-overlapping occurrences of <pattern> (a string or a RE
-repl, string[, object) in <string>by <repl>; <repl> can be a string or a fct
-count=0]) called with a single MatchObj arg, which must return the
- replacement string.
-subn(pattern,
-repl, string[, same as sub(), but returns a tuple (newString, numberOfSubsMade)
-count=0])
-
-Regular Expression Objects
-
-
-(RE objects are returned by the compile fct)
-
- re object attributes
-Attribute Descrition
-flags flags arg used when RE obj was compiled, or 0 if none provided
-groupindex dictionary of {group name: group number} in pattern
-pattern pattern string from which RE obj was compiled
-
- re object methods
- Method Result
- If zero or more characters at the beginning of string match this
- regular expression, return a corresponding MatchObject instance.
- Return None if the string does not match the pattern; note that
- this is different from a zero-length match.
- The optional second parameter pos gives an index in the string
-match( where the search is to start; it defaults to 0. This is not
-string[, completely equivalent to slicing the string; the '' pattern
-pos][, character matches at the real beginning of the string and at
-endpos]) positions just after a newline, but not necessarily at the index
- where the search is to start.
- The optional parameter endpos limits how far the string will be
- searched; it will be as if the string is endpos characters long, so
- only the characters from pos to endpos will be searched for a
- match.
- Scan through string looking for a location where this regular
-search( expression produces a match, and return a corresponding MatchObject
-string[, instance. Return None if no position in the string matches the
-pos][, pattern; note that this is different from finding a zero-length
-endpos]) match at some point in the string.
- The optional pos and endpos parameters have the same meaning as for
- the match() method.
-split(
-string[, Identical to the split() function, using the compiled pattern.
-maxsplit=
-0])
-findall( Identical to the findall() function, using the compiled pattern.
-string)
-sub(repl,
-string[, Identical to the sub() function, using the compiled pattern.
-count=0])
-subn(repl,
-string[, Identical to the subn() function, using the compiled pattern.
-count=0])
-
-Match Objects
-
-
-(Match objects are returned by the match & search functions)
-
- Match object attributes
-Attribute Description
-pos value of pos passed to search or match functions; index intostring at
- which RE engine started search.
-endpos value of endpos passed to search or match functions; index intostring
- beyond which RE engine won't go.
-re RE object whose match or search fct produced this MatchObj instance
-string string passed to match() or search()
-
- Match object functions
-Function Result
- returns one or more groups of the match. If one arg, result is a
-group([g1 string;if multiple args, result is a tuple with one item per arg. If
-, g2, gi is 0,return value is entire matching string; if 1 <= gi <= 99,
-...]) returnstring matching group #gi (or None if no such group); gi may
- also bea group name.
- returns a tuple of all groups of the match; groups not
-groups() participatingto the match have a value of None. Returns a string
- instead of tupleif len(tuple)=1
-start(
-group), returns indices of start & end of substring matched by group (or
-end(group Noneif group exists but doesn't contribute to the match)
-)
-span( returns the 2-tuple (start(group), end(group)); can be (None, None)if
-group) group didn't contibute to the match.
-
-
-
- math
-
-Variables:
-pi
-e
-Functions (see ordinary C man pages for info):
-acos(x)
-asin(x)
-atan(x)
-atan2(x, y)
-ceil(x)
-cos(x)
-cosh(x)
-degrees(x)
-exp(x)
-fabs(x)
-floor(x)
-fmod(x, y)
-frexp(x) -- Unlike C: (float, int) = frexp(float)
-ldexp(x, y)
-log(x [,base])
-log10(x)
-modf(x) -- Unlike C: (float, float) = modf(float)
-pow(x, y)
-radians(x)
-sin(x)
-sinh(x)
-sqrt(x)
-tan(x)
-tanh(x)
-
- getopt
-
-Functions:
-getopt(list, optstr) -- Similar to C. <optstr> is option
- letters to look for. Put ':' after letter
- if option takes arg. E.g.
- # invocation was "python test.py -c hi -a arg1 arg2"
- opts, args = getopt.getopt(sys.argv[1:], 'ab:c:')
- # opts would be
- [('-c', 'hi'), ('-a', '')]
- # args would be
- ['arg1', 'arg2']
-
-
-List of modules and packages in base distribution
-
-(built-ins and content of python Lib directory)
-(Python NT distribution, may be slightly different in other distributions)
-
- Standard library modules
- Operation Result
-aifc Stuff to parse AIFF-C and AIFF files.
-asynchat Support for 'chat' style protocols
-asyncore Asynchronous File I/O (in select style)
-atexit Register functions to be called at exit of Python interpreter.
-base64 Conversions to/from base64 RFC-MIME transport encoding .
-bdb A generic Python debugger base class.
-binhex Macintosh binhex compression/decompression.
-bisect List bisection algorithms.
-bz2 Support for bz2 compression/decompression.
-calendar Calendar printing functions.
-cgi Wraps the WWW Forms Common Gateway Interface (CGI).
-cgitb Utility for handling CGI tracebacks.
-cmd A generic class to build line-oriented command interpreters.
-datetime Basic date and time types.
-code Utilities needed to emulate Python's interactive interpreter
-codecs Lookup existing Unicode encodings and register new ones.
-colorsys Conversion functions between RGB and other color systems.
-compileall Force "compilation" of all .py files in a directory.
-configparser Configuration file parser (much like windows .ini files)
-copy Generic shallow and deep copying operations.
-copyreg Helper to provide extensibility for pickle/cPickle.
-csv Read and write files with comma separated values.
-dbm Generic interface to all dbm clones (dbm.bsd, dbm.gnu,
- dbm.ndbm, dbm.dumb).
-dircache Sorted list of files in a dir, using a cache.
-difflib Tool for creating delta between sequences.
-dis Bytecode disassembler.
-distutils Package installation system.
-doctest Tool for running and verifying tests inside doc strings.
-dospath Common operations on DOS pathnames.
-email Comprehensive support for internet email.
-filecmp File comparison.
-fileinput Helper class to quickly write a loop over all standard input
- files.
-fnmatch Filename matching with shell patterns.
-formatter A test formatter.
-fpformat General floating point formatting functions.
-ftplib An FTP client class. Based on RFC 959.
-gc Perform garbacge collection, obtain GC debug stats, and tune
- GC parameters.
-getopt Standard command line processing. See also ftp://
- www.pauahtun.org/pub/getargspy.zip
-getpass Utilities to get a password and/or the current user name.
-glob filename globbing.
-gzip Read & write gzipped files.
-heapq Priority queue implemented using lists organized as heaps.
-hmac Keyed-Hashing for Message Authentication -- RFC 2104.
-html.entities HTML entity definitions.
-html.parser A parser for HTML and XHTML.
-http.client HTTP client class.
-http.server HTTP server services.
-ihooks Hooks into the "import" mechanism.
-imaplib IMAP4 client.Based on RFC 2060.
-imghdr Recognizing image files based on their first few bytes.
-imputil Privides a way of writing customised import hooks.
-inspect Tool for probing live Python objects.
-keyword List of Python keywords.
-linecache Cache lines from files.
-locale Support for number formatting using the current locale
- settings.
-logging Python logging facility.
-macpath Pathname (or related) operations for the Macintosh.
-macurl2path Mac specific module for conversion between pathnames and URLs.
-mailbox A class to handle a unix-style or mmdf-style mailbox.
-mailcap Mailcap file handling (RFC 1524).
-mhlib MH (mailbox) interface.
-mimetypes Guess the MIME type of a file.
-mmap Interface to memory-mapped files - they behave like mutable
- strings./font>
-multifile Class to make multi-file messages easier to handle.
-mutex Mutual exclusion -- for use with module sched.
-netrc
-nntplib An NNTP client class. Based on RFC 977.
-ntpath Common operations on DOS pathnames.
-nturl2path Mac specific module for conversion between pathnames and URLs.
-optparse A comprehensive tool for processing command line options.
-os Either mac, dos or posix depending system.
-pdb A Python debugger.
-pickle Pickling (save and restore) of Python objects (a faster
- Cimplementation exists in built-in module: cPickle).
-pipes Conversion pipeline templates.
-pkgunil Utilities for working with Python packages.
-poplib A POP3 client class. Based on the J. Myers POP3 draft.
-posixpath Common operations on POSIX pathnames.
-pprint Support to pretty-print lists, tuples, & dictionaries
- recursively.
-profile Class for profiling python code.
-pstats Class for printing reports on profiled python code.
-pydoc Utility for generating documentation from source files.
-pty Pseudo terminal utilities.
-pyexpat Interface to the Expay XML parser.
-py_compile Routine to "compile" a .py file to a .pyc file.
-pyclbr Parse a Python file and retrieve classes and methods.
-queue A multi-producer, multi-consumer queue.
-quopri Conversions to/from quoted-printable transport encoding.
-random Random variable generators
-re Regular Expressions.
-reprlib Redo repr() but with limits on most sizes.
-rlcompleter Word completion for GNU readline 2.0.
-sched A generally useful event scheduler class.
-shelve Manage shelves of pickled objects.
-shlex Lexical analyzer class for simple shell-like syntaxes.
-shutil Utility functions usable in a shell-like program.
-site Append module search paths for third-party packages to
- sys.path.
-smtplib SMTP Client class (RFC 821)
-sndhdr Several routines that help recognizing sound.
-socketserver Generic socket server classes.
-stat Constants and functions for interpreting stat/lstat struct.
-statvfs Constants for interpreting statvfs struct as returned by
- os.statvfs()and os.fstatvfs() (if they exist).
-string A collection of string operations.
-sunau Stuff to parse Sun and NeXT audio files.
-sunaudio Interpret sun audio headers.
-symbol Non-terminal symbols of Python grammar (from "graminit.h").
-tabnanny Check Python source for ambiguous indentation.
-tarfile Facility for reading and writing to the *nix tarfile format.
-telnetlib TELNET client class. Based on RFC 854.
-tempfile Temporary file name allocation.
-textwrap Object for wrapping and filling text.
-threading Proposed new higher-level threading interfaces
-token Tokens (from "token.h").
-tokenize Compiles a regular expression that recognizes Python tokens.
-traceback Format and print Python stack traces.
-tty Terminal utilities.
-turtle LogoMation-like turtle graphics
-types Define names for all type symbols in the std interpreter.
-tzparse Parse a timezone specification.
-unicodedata Interface to unicode properties.
-urllib.parse Parse URLs according to latest draft of standard.
-urllib.request Open an arbitrary URL.
-urllib.robotparser Parse robots.txt files, useful for web spiders.
-user Hook to allow user-specified customization code to run.
-uu UUencode/UUdecode.
-unittest Utilities for implementing unit testing.
-wave Stuff to parse WAVE files.
-weakref Tools for creating and managing weakly referenced objects.
-webbrowser Platform independent URL launcher.
-xdrlib Implements (a subset of) Sun XDR (eXternal Data
- Representation).
-xml.dom Classes for processing XML using the Document Object Model.
-xml.sax Classes for processing XML using the SAX API.
-xmlrpc.client Support for remote procedure calls using XML.
-xmlrpc.server Create XMLRPC servers.
-zipfile Read & write PK zipped files.
-
-
-
-* Built-ins *
-
- sys Interpreter state vars and functions
- __built-in__ Access to all built-in python identifiers
- __main__ Scope of the interpreters main program, script or stdin
- array Obj efficiently representing arrays of basic values
- math Math functions of C standard
- time Time-related functions (also the newer datetime module)
- marshal Read and write some python values in binary format
- struct Convert between python values and C structs
-
-* Standard *
-
- getopt Parse cmd line args in sys.argv. A la UNIX 'getopt'.
- os A more portable interface to OS dependent functionality
- re Functions useful for working with regular expressions
- string Useful string and characters functions and exceptions
- random Mersenne Twister pseudo-random number generator
- _thread Low-level primitives for working with process threads
- threading idem, new recommended interface.
-
-* Unix/Posix *
-
- dbm Interface to Unix dbm databases
- grp Interface to Unix group database
- posix OS functionality standardized by C and POSIX standards
- posixpath POSIX pathname functions
- pwd Access to the Unix password database
- select Access to Unix select multiplex file synchronization
- socket Access to BSD socket interface
-
-* Tk User-interface Toolkit *
-
- tkinter Main interface to Tk
-
-* Multimedia *
-
- audioop Useful operations on sound fragments
- imageop Useful operations on images
- jpeg Access to jpeg image compressor and decompressor
- rgbimg Access SGI imglib image files
-
-* Cryptographic Extensions *
-
- md5 Interface to RSA's MD5 message digest algorithm
- sha Interface to the SHA message digest algorithm
- HMAC Keyed-Hashing for Message Authentication -- RFC 2104.
-
-* SGI IRIX * (4 & 5)
-
- al SGI audio facilities
- AL al constants
- fl Interface to FORMS library
- FL fl constants
- flp Functions for form designer
- fm Access to font manager library
- gl Access to graphics library
- GL Constants for gl
- DEVICE More constants for gl
- imgfile Imglib image file interface
-
-
-Workspace exploration and idiom hints
-
- dir(<module>) list functions, variables in <module>
- dir() get object keys, defaults to local name space
- if __name__ == '__main__': main() invoke main if running as script
- map(None, lst1, lst2, ...) merge lists
- b = a[:] create copy of seq structure
- _ in interactive mode, is last value printed
-
-
-
-
-
-
-
-Python Mode for Emacs
-
-(Not revised, possibly not up to date)
-Type C-c ? when in python-mode for extensive help.
-INDENTATION
-Primarily for entering new code:
- TAB indent line appropriately
- LFD insert newline, then indent
- DEL reduce indentation, or delete single character
-Primarily for reindenting existing code:
- C-c : guess py-indent-offset from file content; change locally
- C-u C-c : ditto, but change globally
- C-c TAB reindent region to match its context
- C-c < shift region left by py-indent-offset
- C-c > shift region right by py-indent-offset
-MARKING & MANIPULATING REGIONS OF CODE
-C-c C-b mark block of lines
-M-C-h mark smallest enclosing def
-C-u M-C-h mark smallest enclosing class
-C-c # comment out region of code
-C-u C-c # uncomment region of code
-MOVING POINT
-C-c C-p move to statement preceding point
-C-c C-n move to statement following point
-C-c C-u move up to start of current block
-M-C-a move to start of def
-C-u M-C-a move to start of class
-M-C-e move to end of def
-C-u M-C-e move to end of class
-EXECUTING PYTHON CODE
-C-c C-c sends the entire buffer to the Python interpreter
-C-c | sends the current region
-C-c ! starts a Python interpreter window; this will be used by
- subsequent C-c C-c or C-c | commands
-C-c C-w runs PyChecker
-
-VARIABLES
-py-indent-offset indentation increment
-py-block-comment-prefix comment string used by py-comment-region
-py-python-command shell command to invoke Python interpreter
-py-scroll-process-buffer t means always scroll Python process buffer
-py-temp-directory directory used for temp files (if needed)
-py-beep-if-tab-change ring the bell if tab-width is changed
-
-
-The Python Debugger
-
-(Not revised, possibly not up to date, see 1.5.2 Library Ref section 9.1; in 1.5.2, you may also use debugger integrated in IDLE)
-
-Accessing
-
-import pdb (it's a module written in Python)
- -- defines functions :
- run(statement[,globals[, locals]])
- -- execute statement string under debugger control, with optional
- global & local environment.
- runeval(expression[,globals[, locals]])
- -- same as run, but evaluate expression and return value.
- runcall(function[, argument, ...])
- -- run function object with given arg(s)
- pm() -- run postmortem on last exception (like debugging a core file)
- post_mortem(t)
- -- run postmortem on traceback object <t>
-
- -- defines class Pdb :
- use Pdb to create reusable debugger objects. Object
- preserves state (i.e. break points) between calls.
-
- runs until a breakpoint hit, exception, or end of program
- If exception, variable '__exception__' holds (exception,value).
-
-Commands
-
-h, help
- brief reminder of commands
-b, break [<arg>]
- if <arg> numeric, break at line <arg> in current file
- if <arg> is function object, break on entry to fcn <arg>
- if no arg, list breakpoints
-cl, clear [<arg>]
- if <arg> numeric, clear breakpoint at <arg> in current file
- if no arg, clear all breakpoints after confirmation
-w, where
- print current call stack
-u, up
- move up one stack frame (to top-level caller)
-d, down
- move down one stack frame
-s, step
- advance one line in the program, stepping into calls
-n, next
- advance one line, stepping over calls
-r, return
- continue execution until current function returns
- (return value is saved in variable "__return__", which
- can be printed or manipulated from debugger)
-c, continue
- continue until next breakpoint
-j, jump lineno
- Set the next line that will be executed
-a, args
- print args to current function
-rv, retval
- prints return value from last function that returned
-p, print <arg>
- prints value of <arg> in current stack frame
-l, list [<first> [, <last>]]
- List source code for the current file.
- Without arguments, list 11 lines around the current line
- or continue the previous listing.
- With one argument, list 11 lines starting at that line.
- With two arguments, list the given range;
- if the second argument is less than the first, it is a count.
-whatis <arg>
- prints type of <arg>
-!
- executes rest of line as a Python statement in the current stack frame
-q quit
- immediately stop execution and leave debugger
-<return>
- executes last command again
-Any input debugger doesn't recognize as a command is assumed to be a
-Python statement to execute in the current stack frame, the same way
-the exclamation mark ("!") command does.
-
-Example
-
-(1394) python
-Python 1.0.3 (Sep 26 1994)
-Copyright 1991-1994 Stichting Mathematisch Centrum, Amsterdam
->>> import rm
->>> rm.run()
-Traceback (innermost last):
- File "<stdin>", line 1
- File "./rm.py", line 7
- x = div(3)
- File "./rm.py", line 2
- return a / r
-ZeroDivisionError: integer division or modulo
->>> import pdb
->>> pdb.pm()
-> ./rm.py(2)div: return a / r
-(Pdb) list
- 1 def div(a):
- 2 -> return a / r
- 3
- 4 def run():
- 5 global r
- 6 r = 0
- 7 x = div(3)
- 8 print x
-[EOF]
-(Pdb) print r
-0
-(Pdb) q
->>> pdb.runcall(rm.run)
-etc.
-
-Quirks
-
-Breakpoints are stored as filename, line number tuples. If a module is reloaded
-after editing, any remembered breakpoints are likely to be wrong.
-
-Always single-steps through top-most stack frame. That is, "c" acts like "n".
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