diff options
-rw-r--r-- | Doc/library/re.rst | 26 |
1 files changed, 2 insertions, 24 deletions
diff --git a/Doc/library/re.rst b/Doc/library/re.rst index c4ecd46..abbe152 100644 --- a/Doc/library/re.rst +++ b/Doc/library/re.rst @@ -1093,28 +1093,6 @@ The equivalent regular expression would be :: (\S+) - (\d+) errors, (\d+) warnings -Avoiding recursion -^^^^^^^^^^^^^^^^^^ - -If you create regular expressions that require the engine to perform a lot of -recursion, you may encounter a :exc:`RuntimeError` exception with the message -``maximum recursion limit exceeded``. For example, :: - - >>> s = 'Begin ' + 1000*'a very long string ' + 'end' - >>> re.match('Begin (\w| )*? end', s).end() - Traceback (most recent call last): - File "<stdin>", line 1, in ? - File "/usr/local/lib/python3.2/re.py", line 132, in match - return _compile(pattern, flags).match(string) - RuntimeError: maximum recursion limit exceeded - -You can often restructure your regular expression to avoid recursion. - -Simple uses of the ``*?`` pattern are special-cased to avoid recursion. Thus, -the above regular expression can avoid recursion by being recast as ``Begin -[a-zA-Z0-9_ ]*?end``. As a further benefit, such regular expressions will run -faster than their recursive equivalents. - .. _search-vs-match: search() vs. match() @@ -1161,7 +1139,7 @@ creates a phonebook. First, here is the input. Normally it may come from a file, here we are using triple-quoted string syntax: - >>> input = """Ross McFluff: 834.345.1254 155 Elm Street + >>> text = """Ross McFluff: 834.345.1254 155 Elm Street ... ... Ronald Heathmore: 892.345.3428 436 Finley Avenue ... Frank Burger: 925.541.7625 662 South Dogwood Way @@ -1175,7 +1153,7 @@ into a list with each nonempty line having its own entry: .. doctest:: :options: +NORMALIZE_WHITESPACE - >>> entries = re.split("\n+", input) + >>> entries = re.split("\n+", text) >>> entries ['Ross McFluff: 834.345.1254 155 Elm Street', 'Ronald Heathmore: 892.345.3428 436 Finley Avenue', |