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(python2.1-lib.info)Match Objects
Match Objects
-------------
`MatchObject' instances support the following methods and attributes:
`expand(template)'
Return the string obtained by doing backslash substitution on the
template string TEMPLATE, as done by the `sub()' method. Escapes
such as `\n' are converted to the appropriate characters, and
numeric backreferences (`\1', `\2') and named backreferences
(`\g<1>', `\g<name>') are replaced by the contents of the
corresponding group.
`group([group1, ...])'
Returns one or more subgroups of the match. If there is a single
argument, the result is a single string; if there are multiple
arguments, the result is a tuple with one item per argument.
Without arguments, GROUP1 defaults to zero (i.e. the whole match
is returned). If a GROUPN argument is zero, the corresponding
return value is the entire matching string; if it is in the
inclusive range [1..99], it is the string matching the the
corresponding parenthesized group. If a group number is negative
or larger than the number of groups defined in the pattern, an
`IndexError' exception is raised. If a group is contained in a
part of the pattern that did not match, the corresponding result
is `None'. If a group is contained in a part of the pattern that
matched multiple times, the last match is returned.
If the regular expression uses the "(?P<NAME>...)" syntax, the
GROUPN arguments may also be strings identifying groups by their
group name. If a string argument is not used as a group name in
the pattern, an `IndexError' exception is raised.
A moderately complicated example:
m = re.match(r"(?P<int>\d+)\.(\d*)", '3.14')
After performing this match, `m.group(1)' is `'3'', as is
`m.group('int')', and `m.group(2)' is `'14''.
`groups([default])'
Return a tuple containing all the subgroups of the match, from 1
up to however many groups are in the pattern. The DEFAULT
argument is used for groups that did not participate in the match;
it defaults to `None'. (Incompatibility note: in the original
Python 1.5 release, if the tuple was one element long, a string
would be returned instead. In later versions (from 1.5.1 on), a
singleton tuple is returned in such cases.)
`groupdict([default])'
Return a dictionary containing all the _named_ subgroups of the
match, keyed by the subgroup name. The DEFAULT argument is used
for groups that did not participate in the match; it defaults to
`None'.
`start([group])'
`end [group]'
Return the indices of the start and end of the substring matched
by GROUP; GROUP defaults to zero (meaning the whole matched
substring). Return `-1' if GROUP exists but did not contribute to
the match. For a match object M, and a group G that did
contribute to the match, the substring matched by group G
(equivalent to `M.group(G)') is
m.string[m.start(g):m.end(g)]
Note that `m.start(GROUP)' will equal `m.end(GROUP)' if GROUP
matched a null string. For example, after `M = re.search('b(c?)',
'cba')', `M.start(0)' is 1, `M.end(0)' is 2, `M.start(1)' and
`M.end(1)' are both 2, and `M.start(2)' raises an `IndexError'
exception.
`span([group])'
For `MatchObject' M, return the 2-tuple `(M.start(GROUP),
M.end(GROUP))'. Note that if GROUP did not contribute to the
match, this is `(-1, -1)'. Again, GROUP defaults to zero.
`pos'
The value of POS which was passed to the `search()' or `match()'
function. This is the index into the string at which the RE
engine started looking for a match.
`endpos'
The value of ENDPOS which was passed to the `search()' or
`match()' function. This is the index into the string beyond
which the RE engine will not go.
`lastgroup'
The name of the last matched capturing group, or `None' if the
group didn't have a name, or if no group was matched at all.
`lastindex'
The integer index of the last matched capturing group, or `None'
if no group was matched at all.
`re'
The regular expression object whose `match()' or `search()' method
produced this `MatchObject' instance.
`string'
The string passed to `match()' or `search()'.
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