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author | Georg Brandl <georg@python.org> | 2012-03-17 16:25:47 (GMT) |
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committer | Georg Brandl <georg@python.org> | 2012-03-17 16:25:47 (GMT) |
commit | ce54617260790a523c246a1f4080b8e82386cd20 (patch) | |
tree | 2735aecfd246c0dfde5b36e873fce532c1930069 | |
parent | f354f8e369e1e903d489e6dbac01f94d905dc022 (diff) | |
download | cpython-ce54617260790a523c246a1f4080b8e82386cd20.zip cpython-ce54617260790a523c246a1f4080b8e82386cd20.tar.gz cpython-ce54617260790a523c246a1f4080b8e82386cd20.tar.bz2 |
Closes #14342: remove out-of-date section about avoiding recursion errors.
-rw-r--r-- | Doc/library/re.rst | 22 |
1 files changed, 0 insertions, 22 deletions
diff --git a/Doc/library/re.rst b/Doc/library/re.rst index e3bac50..c2ac332 100644 --- a/Doc/library/re.rst +++ b/Doc/library/re.rst @@ -1077,28 +1077,6 @@ 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/python2.5/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. - -Starting with Python 2.3, 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() |