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Add re.fullmatch() function and regex.fullmatch() method, which anchor the
pattern at both ends of the string to match. Patch by Matthew Barnett. Closes #16203.
1 parent 57841dd commit 4300019

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Lines changed: 156 additions & 45 deletions

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‎Doc/library/re.rst‎

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@@ -584,6 +584,16 @@ form.
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instead (see also :ref:`search-vs-match`).
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.. function:: fullmatch(pattern, string, flags=0)
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If the whole *string* matches the regular expression *pattern*, return a
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corresponding :ref:`match object <match-objects>`. Return ``None`` if the
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string does not match the pattern; note that this is different from a
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zero-length match.
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.. versionadded:: 3.4
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.. function:: split(pattern, string, maxsplit=0, flags=0)
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Split *string* by the occurrences of *pattern*. If capturing parentheses are
@@ -778,6 +788,24 @@ attributes:
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:meth:`~regex.search` instead (see also :ref:`search-vs-match`).
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.. method:: regex.fullmatch(string[, pos[, endpos]])
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If the whole *string* matches this regular expression, return a corresponding
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:ref:`match object <match-objects>`. Return ``None`` if the string does not
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match the pattern; note that this is different from a zero-length match.
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The optional *pos* and *endpos* parameters have the same meaning as for the
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:meth:`~regex.search` method.
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>>> pattern = re.compile("o[gh]")
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>>> pattern.fullmatch("dog") # No match as "o" is not at the start of "dog".
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>>> pattern.fullmatch("ogre") # No match as not the full string matches.
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>>> pattern.fullmatch("doggie", 1, 3) # Matches within given limits.
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<_sre.SRE_Match object at ...>
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.. versionadded:: 3.4
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.. method:: regex.split(string, maxsplit=0)
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Identical to the :func:`split` function, using the compiled pattern.

‎Lib/re.py‎

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\\ Matches a literal backslash.
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This module exports the following functions:
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match Match a regular expression pattern to the beginning of a string.
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search Search a string for the presence of a pattern.
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sub Substitute occurrences of a pattern found in a string.
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subn Same as sub, but also return the number of substitutions made.
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split Split a string by the occurrences of a pattern.
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findall Find all occurrences of a pattern in a string.
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finditer Return an iterator yielding a match object for each match.
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compile Compile a pattern into a RegexObject.
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purge Clear the regular expression cache.
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escape Backslash all non-alphanumerics in a string.
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match Match a regular expression pattern to the beginning of a string.
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fullmatch Match a regular expression pattern to all of a string.
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search Search a string for the presence of a pattern.
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sub Substitute occurrences of a pattern found in a string.
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subn Same as sub, but also return the number of substitutions made.
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split Split a string by the occurrences of a pattern.
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findall Find all occurrences of a pattern in a string.
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finditer Return an iterator yielding a match object for each match.
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compile Compile a pattern into a RegexObject.
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purge Clear the regular expression cache.
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escape Backslash all non-alphanumerics in a string.
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Some of the functions in this module takes flags as optional parameters:
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A ASCII For string patterns, make \w, \W, \b, \B, \d, \D
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import sre_parse
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# public symbols
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__all__ = [ "match", "search", "sub", "subn", "split", "findall",
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__all__ = [ "match", "fullmatch", "search", "sub", "subn", "split", "findall",
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"compile", "purge", "template", "escape", "A", "I", "L", "M", "S", "X",
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"U", "ASCII", "IGNORECASE", "LOCALE", "MULTILINE", "DOTALL", "VERBOSE",
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"UNICODE", "error" ]
@@ -154,6 +155,11 @@ def match(pattern, string, flags=0):
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a match object, or None if no match was found."""
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return _compile(pattern, flags).match(string)
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def fullmatch(pattern, string, flags=0):
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"""Try to apply the pattern to all of the string, returning
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a match object, or None if no match was found."""
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return _compile(pattern, flags).fullmatch(string)
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def search(pattern, string, flags=0):
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"""Scan through string looking for a match to the pattern, returning
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a match object, or None if no match was found."""

‎Lib/test/test_re.py‎

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self.assertEqual(m.group(1), "")
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self.assertEqual(m.group(2), "y")
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def test_fullmatch(self):
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# Issue 16203: Proposal: add re.fullmatch() method.
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self.assertEqual(re.fullmatch(r"a", "a").span(), (0, 1))
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self.assertEqual(re.fullmatch(r"a|ab", "ab").span(), (0, 2))
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self.assertEqual(re.fullmatch(r".*?$", "abc").span(), (0, 3))
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self.assertEqual(re.fullmatch(r".*?", "abc").span(), (0, 3))
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self.assertEqual(re.fullmatch(r"a.*?b", "ab").span(), (0, 2))
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self.assertEqual(re.fullmatch(r"a.*?b", "abb").span(), (0, 3))
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self.assertEqual(re.fullmatch(r"a.*?b", "axxb").span(), (0, 4))
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self.assertEqual(re.fullmatch(r"abc$", "abc\n"), None)
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self.assertEqual(re.fullmatch(r"abc\Z", "abc\n"), None)
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self.assertEqual(re.fullmatch(r"(?m)abc$", "abc\n"), None)
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self.assertEqual(re.fullmatch(r"ab(?=c)cd", "abcd").span(), (0, 4))
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self.assertEqual(re.fullmatch(r"ab(?<=b)cd", "abcd").span(), (0, 4))
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self.assertEqual(re.fullmatch(r"(?=a|ab)ab", "ab").span(), (0, 2))
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self.assertEqual(
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re.compile(r"bc").fullmatch("abcd", pos=1, endpos=3).span(), (1, 3))
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self.assertEqual(
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re.compile(r".*?$").fullmatch("abcd", pos=1, endpos=3).span(), (1, 3))
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self.assertEqual(
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re.compile(r".*?").fullmatch("abcd", pos=1, endpos=3).span(), (1, 3))
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def run_re_tests():
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from test.re_tests import tests, SUCCEED, FAIL, SYNTAX_ERROR
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if verbose:

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