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@ -354,9 +354,9 @@ for a complete listing. |
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+------------------+-----------------------------------------------+ |
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:meth:`match` and :meth:`search` return ``None`` if no match can be found. If |
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they're successful, a ``MatchObject`` instance is returned, containing |
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information about the match: where it starts and ends, the substring it matched, |
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and more. |
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they're successful, a :ref:`match object <match-objects>` instance is returned, |
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containing information about the match: where it starts and ends, the substring |
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it matched, and more. |
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You can learn about this by interactively experimenting with the :mod:`re` |
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module. If you have :mod:`tkinter` available, you may also want to look at |
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@ -386,16 +386,16 @@ interpreter to print no output. You can explicitly print the result of |
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None |
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Now, let's try it on a string that it should match, such as ``tempo``. In this |
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case, :meth:`match` will return a :class:`MatchObject`, so you should store the |
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result in a variable for later use. :: |
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case, :meth:`match` will return a :ref:`match object <match-objects>`, so you |
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should store the result in a variable for later use. :: |
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>>> m = p.match('tempo') |
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>>> m #doctest: +ELLIPSIS |
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<_sre.SRE_Match object at 0x...> |
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Now you can query the :class:`MatchObject` for information about the matching |
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string. :class:`MatchObject` instances also have several methods and |
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attributes; the most important ones are: |
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Now you can query the :ref:`match object <match-objects>` for information |
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about the matching string. :ref:`match object <match-objects>` instances |
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also have several methods and attributes; the most important ones are: |
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+------------------+--------------------------------------------+ |
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| Method/Attribute | Purpose | |
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@ -436,8 +436,9 @@ case. :: |
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>>> m.span() |
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(4, 11) |
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In actual programs, the most common style is to store the :class:`MatchObject` |
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in a variable, and then check if it was ``None``. This usually looks like:: |
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In actual programs, the most common style is to store the |
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:ref:`match object <match-objects>` in a variable, and then check if it was |
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``None``. This usually looks like:: |
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p = re.compile( ... ) |
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m = p.match( 'string goes here' ) |
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@ -454,8 +455,8 @@ Two pattern methods return all of the matches for a pattern. |
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['12', '11', '10'] |
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:meth:`findall` has to create the entire list before it can be returned as the |
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result. The :meth:`finditer` method returns a sequence of :class:`MatchObject` |
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instances as an :term:`iterator`:: |
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result. The :meth:`finditer` method returns a sequence of |
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:ref:`match object <match-objects>` instances as an :term:`iterator`:: |
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>>> iterator = p.finditer('12 drummers drumming, 11 ... 10 ...') |
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>>> iterator #doctest: +ELLIPSIS |
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@ -476,7 +477,7 @@ You don't have to create a pattern object and call its methods; the |
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:func:`search`, :func:`findall`, :func:`sub`, and so forth. These functions |
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take the same arguments as the corresponding pattern method, with |
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the RE string added as the first argument, and still return either ``None`` or a |
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:class:`MatchObject` instance. :: |
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:ref:`match object <match-objects>` instance. :: |
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>>> print(re.match(r'From\s+', 'Fromage amk')) |
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None |
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@ -786,9 +787,9 @@ Groups indicated with ``'('``, ``')'`` also capture the starting and ending |
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index of the text that they match; this can be retrieved by passing an argument |
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to :meth:`group`, :meth:`start`, :meth:`end`, and :meth:`span`. Groups are |
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numbered starting with 0. Group 0 is always present; it's the whole RE, so |
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:class:`MatchObject` methods all have group 0 as their default argument. Later |
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we'll see how to express groups that don't capture the span of text that they |
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match. :: |
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:ref:`match object <match-objects>` methods all have group 0 as their default |
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argument. Later we'll see how to express groups that don't capture the span |
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of text that they match. :: |
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>>> p = re.compile('(a)b') |
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>>> m = p.match('ab') |
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@ -908,10 +909,10 @@ numbers, groups can be referenced by a name. |
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The syntax for a named group is one of the Python-specific extensions: |
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``(?P<name>...)``. *name* is, obviously, the name of the group. Named groups |
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also behave exactly like capturing groups, and additionally associate a name |
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with a group. The :class:`MatchObject` methods that deal with capturing groups |
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all accept either integers that refer to the group by number or strings that |
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contain the desired group's name. Named groups are still given numbers, so you |
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can retrieve information about a group in two ways:: |
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with a group. The :ref:`match object <match-objects>` methods that deal with |
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capturing groups all accept either integers that refer to the group by number |
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or strings that contain the desired group's name. Named groups are still |
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given numbers, so you can retrieve information about a group in two ways:: |
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>>> p = re.compile(r'(?P<word>\b\w+\b)') |
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>>> m = p.search( '(((( Lots of punctuation )))' ) |
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@ -1175,11 +1176,11 @@ three variations of the replacement string. :: |
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*replacement* can also be a function, which gives you even more control. If |
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*replacement* is a function, the function is called for every non-overlapping |
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occurrence of *pattern*. On each call, the function is passed a |
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:class:`MatchObject` argument for the match and can use this information to |
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compute the desired replacement string and return it. |
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occurrence of *pattern*. On each call, the function is passed a |
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:ref:`match object <match-objects>` argument for the match and can use this |
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information to compute the desired replacement string and return it. |
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In the following example, the replacement function translates decimals into |
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In the following example, the replacement function translates decimals into |
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hexadecimal:: |
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>>> def hexrepl(match): |
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