#16760: merge with 3.3.

This commit is contained in:
Ezio Melotti 2012-12-25 18:16:31 +02:00
commit e34ccb6861
1 changed files with 25 additions and 24 deletions

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@ -354,9 +354,9 @@ for a complete listing.
+------------------+-----------------------------------------------+ +------------------+-----------------------------------------------+
:meth:`match` and :meth:`search` return ``None`` if no match can be found. If :meth:`match` and :meth:`search` return ``None`` if no match can be found. If
they're successful, a ``MatchObject`` instance is returned, containing they're successful, a :ref:`match object <match-objects>` instance is returned,
information about the match: where it starts and ends, the substring it matched, containing information about the match: where it starts and ends, the substring
and more. it matched, and more.
You can learn about this by interactively experimenting with the :mod:`re` You can learn about this by interactively experimenting with the :mod:`re`
module. If you have :mod:`tkinter` available, you may also want to look at module. If you have :mod:`tkinter` available, you may also want to look at
@ -386,16 +386,16 @@ interpreter to print no output. You can explicitly print the result of
None None
Now, let's try it on a string that it should match, such as ``tempo``. In this Now, let's try it on a string that it should match, such as ``tempo``. In this
case, :meth:`match` will return a :class:`MatchObject`, so you should store the case, :meth:`match` will return a :ref:`match object <match-objects>`, so you
result in a variable for later use. :: should store the result in a variable for later use. ::
>>> m = p.match('tempo') >>> m = p.match('tempo')
>>> m #doctest: +ELLIPSIS >>> m #doctest: +ELLIPSIS
<_sre.SRE_Match object at 0x...> <_sre.SRE_Match object at 0x...>
Now you can query the :class:`MatchObject` for information about the matching Now you can query the :ref:`match object <match-objects>` for information
string. :class:`MatchObject` instances also have several methods and about the matching string. :ref:`match object <match-objects>` instances
attributes; the most important ones are: also have several methods and attributes; the most important ones are:
+------------------+--------------------------------------------+ +------------------+--------------------------------------------+
| Method/Attribute | Purpose | | Method/Attribute | Purpose |
@ -436,8 +436,9 @@ case. ::
>>> m.span() >>> m.span()
(4, 11) (4, 11)
In actual programs, the most common style is to store the :class:`MatchObject` In actual programs, the most common style is to store the
in a variable, and then check if it was ``None``. This usually looks like:: :ref:`match object <match-objects>` in a variable, and then check if it was
``None``. This usually looks like::
p = re.compile( ... ) p = re.compile( ... )
m = p.match( 'string goes here' ) m = p.match( 'string goes here' )
@ -454,8 +455,8 @@ Two pattern methods return all of the matches for a pattern.
['12', '11', '10'] ['12', '11', '10']
:meth:`findall` has to create the entire list before it can be returned as the :meth:`findall` has to create the entire list before it can be returned as the
result. The :meth:`finditer` method returns a sequence of :class:`MatchObject` result. The :meth:`finditer` method returns a sequence of
instances as an :term:`iterator`:: :ref:`match object <match-objects>` instances as an :term:`iterator`::
>>> iterator = p.finditer('12 drummers drumming, 11 ... 10 ...') >>> iterator = p.finditer('12 drummers drumming, 11 ... 10 ...')
>>> iterator #doctest: +ELLIPSIS >>> iterator #doctest: +ELLIPSIS
@ -476,7 +477,7 @@ You don't have to create a pattern object and call its methods; the
:func:`search`, :func:`findall`, :func:`sub`, and so forth. These functions :func:`search`, :func:`findall`, :func:`sub`, and so forth. These functions
take the same arguments as the corresponding pattern method, with take the same arguments as the corresponding pattern method, with
the RE string added as the first argument, and still return either ``None`` or a the RE string added as the first argument, and still return either ``None`` or a
:class:`MatchObject` instance. :: :ref:`match object <match-objects>` instance. ::
>>> print(re.match(r'From\s+', 'Fromage amk')) >>> print(re.match(r'From\s+', 'Fromage amk'))
None None
@ -786,9 +787,9 @@ Groups indicated with ``'('``, ``')'`` also capture the starting and ending
index of the text that they match; this can be retrieved by passing an argument index of the text that they match; this can be retrieved by passing an argument
to :meth:`group`, :meth:`start`, :meth:`end`, and :meth:`span`. Groups are to :meth:`group`, :meth:`start`, :meth:`end`, and :meth:`span`. Groups are
numbered starting with 0. Group 0 is always present; it's the whole RE, so numbered starting with 0. Group 0 is always present; it's the whole RE, so
:class:`MatchObject` methods all have group 0 as their default argument. Later :ref:`match object <match-objects>` methods all have group 0 as their default
we'll see how to express groups that don't capture the span of text that they argument. Later we'll see how to express groups that don't capture the span
match. :: of text that they match. ::
>>> p = re.compile('(a)b') >>> p = re.compile('(a)b')
>>> m = p.match('ab') >>> m = p.match('ab')
@ -908,10 +909,10 @@ numbers, groups can be referenced by a name.
The syntax for a named group is one of the Python-specific extensions: The syntax for a named group is one of the Python-specific extensions:
``(?P<name>...)``. *name* is, obviously, the name of the group. Named groups ``(?P<name>...)``. *name* is, obviously, the name of the group. Named groups
also behave exactly like capturing groups, and additionally associate a name also behave exactly like capturing groups, and additionally associate a name
with a group. The :class:`MatchObject` methods that deal with capturing groups with a group. The :ref:`match object <match-objects>` methods that deal with
all accept either integers that refer to the group by number or strings that capturing groups all accept either integers that refer to the group by number
contain the desired group's name. Named groups are still given numbers, so you or strings that contain the desired group's name. Named groups are still
can retrieve information about a group in two ways:: given numbers, so you can retrieve information about a group in two ways::
>>> p = re.compile(r'(?P<word>\b\w+\b)') >>> p = re.compile(r'(?P<word>\b\w+\b)')
>>> m = p.search( '(((( Lots of punctuation )))' ) >>> m = p.search( '(((( Lots of punctuation )))' )
@ -1176,8 +1177,8 @@ three variations of the replacement string. ::
*replacement* can also be a function, which gives you even more control. If *replacement* can also be a function, which gives you even more control. If
*replacement* is a function, the function is called for every non-overlapping *replacement* is a function, the function is called for every non-overlapping
occurrence of *pattern*. On each call, the function is passed a occurrence of *pattern*. On each call, the function is passed a
:class:`MatchObject` argument for the match and can use this information to :ref:`match object <match-objects>` argument for the match and can use this
compute the desired replacement string and return it. information to compute the desired replacement string and return it.
In the following example, the replacement function translates decimals into In the following example, the replacement function translates decimals into
hexadecimal:: hexadecimal::