>>> valedictorian = max((student.gpa, student.name) for student in graduates)
>>> data = 'golf'
- >>> list(data[i] for i in range(len(data)-1,-1,-1))
+ >>> list(data[i] for i in range(len(data)-1, -1, -1))
['f', 'l', 'o', 'g']
... """Print a Fibonacci series up to n."""
... a, b = 0, 1
... while b < n:
- ... print(b,end=' ')
+ ... print(b, end=' ')
... a, b = b, a+b
... print()
...
value``. For instance, the following function::
def parrot(voltage, state='a stiff', action='voom', type='Norwegian Blue'):
- print("-- This parrot wouldn't", action, end= ' ')
+ print("-- This parrot wouldn't", action, end=' ')
print("if you put", voltage, "volts through it.")
print("-- Lovely plumage, the", type)
print("-- It's", state, "!")
parameters, because they scoop up all remaining input arguments that are
passed to the function. Any formal parameters which occur after the ``*args``
parameter are 'keyword-only' arguments, meaning that they can only be used as
-keywords rather than positional arguments.::
+keywords rather than positional arguments. ::
>>> def concat(*args, sep="/"):
... return sep.join(args)
-operator::
>>> def parrot(voltage, state='a stiff', action='voom'):
- ... print("-- This parrot wouldn't", action,end=' ')
+ ... print("-- This parrot wouldn't", action, end=' ')
... print("if you put", voltage, "volts through it.", end=' ')
... print("E's", state, "!")
...
Now we get a little fancier::
- >>> [[x,x**2] for x in vec]
+ >>> [[x, x**2] for x in vec]
[[2, 4], [4, 16], [6, 36]]
Here we apply a method call to each item in a sequence::
>>> [weapon.strip() for weapon in freshfruit]
['banana', 'loganberry', 'passion fruit']
-Using the if-clause we can filter the stream::
+Using the :keyword:`if` clause we can filter the stream::
>>> [3*x for x in vec if x > 3]
[12, 18]
>>> [(x, x**2) for x in vec]
[(2, 4), (4, 16), (6, 36)]
-Here are some nested for's and other fancy behavior::
+Here are some nested for loops and other fancy behavior::
>>> vec1 = [2, 4, 6]
>>> vec2 = [4, 3, -9]
List comprehensions can be applied to complex expressions and nested functions::
- >>> [str(round(355/113.0, i)) for i in range(1,6)]
+ >>> [str(round(355/113.0, i)) for i in range(1, 6)]
['3.1', '3.14', '3.142', '3.1416', '3.14159']
To loop over a sequence in reverse, first specify the sequence in a forward
direction and then call the :func:`reversed` function. ::
- >>> for i in reversed(range(1,10,2)):
+ >>> for i in reversed(range(1, 10, 2)):
... print(i)
...
9
Here are two ways to write a table of squares and cubes::
>>> for x in range(1, 11):
- ... print(repr(x).rjust(2), repr(x*x).rjust(3),end=' ')
+ ... print(repr(x).rjust(2), repr(x*x).rjust(3), end=' ')
... # Note use of 'end' on previous line
... print(repr(x*x*x).rjust(4))
...
9 81 729
10 100 1000
- >>> for x in range(1,11):
+ >>> for x in range(1, 11):
... print('%2d %3d %4d' % (x, x*x, x*x*x))
...
1 1 1
>>> 1j * 1J
(-1+0j)
- >>> 1j * complex(0,1)
+ >>> 1j * complex(0, 1)
(-1+0j)
>>> 3+1j*3
(3+3j)
Strings can be subscripted (indexed); like in C, the first character of a string
has subscript (index) 0. There is no separate character type; a character is
-simply a string of size one. As in Icon, substrings can be specified with the
-*slice notation*: two indices separated by a colon. ::
+simply a string of size one. As in the Icon programming language, substrings
+can be specified with the *slice notation*: two indices separated by a colon.
+::
>>> word[4]
'A'
You can add something to the end of the list::
- >>> p[1].append('xtra')
+ >>> p[1].append('xtra')
>>> p
[1, [2, 3, 'xtra'], 4]
>>> q
files when :option:`-O` is used) for all modules in a directory.
* If using Python in a parallel processing system with a shared file system,
- you need to patch python to disable the creation of the compiled files
+ you need to patch Python to disable the creation of the compiled files
because otherwise the multiple Python interpreters will encounter race
- conditions in creating them.
+ conditions in creating them.
.. _tut-standardmodules:
f = zipfile.ZipFile(self.outfile, 'w', zipfile.ZIP_DEFLATED)
f.write(self.infile)
f.close()
- print('Finished background zip of: ', self.infile)
+ print('Finished background zip of:', self.infile)
background = AsyncZip('mydata.txt', 'myarchive.zip')
background.start()
projects / python / commitdiff