Add optional 4th argument to count(), matching find() etc.

Also change all occurrences of "x == None" to "x is None" (not that it
matters much, these functions are all reimplemented in strop -- but
count() is not).

diff --git a/Lib/string.py b/Lib/string.py
index 99e72751a2cbca5b3158d78c559660b08350b44c..5cf5b6f36711adb223fc8c582991022d57e554b6 100644 (file)
--- a/Lib/string.py
+++ b/Lib/string.py
@@ -121,7 +121,7 @@ def joinfields(words, sep = ' '):
 
 # Find substring, raise exception if not found
 def index(s, sub, i = 0, last=None):
-       if last == None: last = len(s)
+       if last is None: last = len(s)
        res = find(s, sub, i, last)
        if res < 0:
                raise ValueError, 'substring not found in string.index'
@@ -129,17 +129,24 @@ def index(s, sub, i = 0, last=None):
 
 # Find last substring, raise exception if not found
 def rindex(s, sub, i = 0, last=None):
-       if last == None: last = len(s)
+       if last is None: last = len(s)
        res = rfind(s, sub, i, last)
        if res < 0:
                raise ValueError, 'substring not found in string.index'
        return res
 
 # Count non-overlapping occurrences of substring
-def count(s, sub, i = 0):
-       if i < 0: i = max(0, i + len(s))
+def count(s, sub, i = 0, last=None):
+       Slen = len(s)  # cache this value, for speed
+       if last is None:
+               last = Slen
+       elif last < 0:
+               last = max(0, last + Slen)
+       elif last > Slen:
+               last = Slen
+       if i < 0: i = max(0, i + Slen)
        n = len(sub)
-       m = len(s) + 1 - n
+       m = last + 1 - n
        if n == 0: return m-i
        r = 0
        while i < m:
@@ -153,7 +160,7 @@ def count(s, sub, i = 0):
 # Find substring, return -1 if not found
 def find(s, sub, i = 0, last=None):
        Slen = len(s)  # cache this value, for speed
-       if last == None:
+       if last is None:
                last = Slen
        elif last < 0:
                last = max(0, last + Slen)
@@ -170,7 +177,7 @@ def find(s, sub, i = 0, last=None):
 # Find last substring, return -1 if not found
 def rfind(s, sub, i = 0, last=None):
        Slen = len(s)  # cache this value, for speed
-       if last == None:
+       if last is None:
                last = Slen
        elif last < 0:
                last = max(0, last + Slen)

diff --git a/Lib/stringold.py b/Lib/stringold.py
index 99e72751a2cbca5b3158d78c559660b08350b44c..5cf5b6f36711adb223fc8c582991022d57e554b6 100644 (file)
--- a/Lib/stringold.py
+++ b/Lib/stringold.py
@@ -121,7 +121,7 @@ def joinfields(words, sep = ' '):
 
 # Find substring, raise exception if not found
 def index(s, sub, i = 0, last=None):
-       if last == None: last = len(s)
+       if last is None: last = len(s)
        res = find(s, sub, i, last)
        if res < 0:
                raise ValueError, 'substring not found in string.index'
@@ -129,17 +129,24 @@ def index(s, sub, i = 0, last=None):
 
 # Find last substring, raise exception if not found
 def rindex(s, sub, i = 0, last=None):
-       if last == None: last = len(s)
+       if last is None: last = len(s)
        res = rfind(s, sub, i, last)
        if res < 0:
                raise ValueError, 'substring not found in string.index'
        return res
 
 # Count non-overlapping occurrences of substring
-def count(s, sub, i = 0):
-       if i < 0: i = max(0, i + len(s))
+def count(s, sub, i = 0, last=None):
+       Slen = len(s)  # cache this value, for speed
+       if last is None:
+               last = Slen
+       elif last < 0:
+               last = max(0, last + Slen)
+       elif last > Slen:
+               last = Slen
+       if i < 0: i = max(0, i + Slen)
        n = len(sub)
-       m = len(s) + 1 - n
+       m = last + 1 - n
        if n == 0: return m-i
        r = 0
        while i < m:
@@ -153,7 +160,7 @@ def count(s, sub, i = 0):
 # Find substring, return -1 if not found
 def find(s, sub, i = 0, last=None):
        Slen = len(s)  # cache this value, for speed
-       if last == None:
+       if last is None:
                last = Slen
        elif last < 0:
                last = max(0, last + Slen)
@@ -170,7 +177,7 @@ def find(s, sub, i = 0, last=None):
 # Find last substring, return -1 if not found
 def rfind(s, sub, i = 0, last=None):
        Slen = len(s)  # cache this value, for speed
-       if last == None:
+       if last is None:
                last = Slen
        elif last < 0:
                last = max(0, last + Slen)