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authorGuido van Rossum <guido@python.org>1997-12-17 00:23:39 (GMT)
committerGuido van Rossum <guido@python.org>1997-12-17 00:23:39 (GMT)
commite4eb2231fda4fa370296f18a39f710d550ed950c (patch)
treec7516f9fbdb5f7fe387cc474c0e1fec30dc7bcff /Doc/libre.tex
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-rw-r--r--Doc/libre.tex72
1 files changed, 43 insertions, 29 deletions
diff --git a/Doc/libre.tex b/Doc/libre.tex
index 8e273bc..8397461 100644
--- a/Doc/libre.tex
+++ b/Doc/libre.tex
@@ -4,7 +4,7 @@
\bimodindex{re}
% XXX Remove before 1.5final release.
-{\large\bf This documentation is also preliminary and incomplete. If you
+{\large\bf This documentation is preliminary and incomplete. If you
find a bug or documentation error, or just find something unclear,
please send a message to
\code{string-sig@python.org}, and we'll fix it.}
@@ -485,33 +485,6 @@ The pattern string from which the regex object was compiled.
\subsection{MatchObjects}
\code{Matchobject} instances support the following methods and attributes:
-\begin{funcdesc}{start}{group}
-\end{funcdesc}
-
-\begin{funcdesc}{end}{group}
-Return the indices of the start and end of the substring
-matched by \var{group}. Return \code{None} if \var{group} exists but
-did not contribute to the match. Note that for a match object
-\code{m}, and a group \code{g} that did contribute to the match, the
-substring matched by group \code{g} is
-\bcode\begin{verbatim}
- m.string[m.start(g):m.end(g)]
-\end{verbatim}\ecode
-%
-Note too that \code{m.start(\var{group})} will equal
-\code{m.end(\var{group})} if \var{group} matched a null string. For example,
-after \code{m = re.search('b(c?)', 'cba')}, \code{m.start(0)} is 1,
-\code{m.end(0)} is 2, \code{m.start(1)} and \code{m.end(1)} are both
-2, and \code{m.start(2)} raises an
-\code{IndexError} exception.
-\end{funcdesc}
-
-\begin{funcdesc}{span}{group}
-Return the 2-tuple \code{(start(\var{group}), end(\var{group}))}.
-Note that if \var{group} did not contribute to the match, this is
-\code{(None, None)}.
-\end{funcdesc}
-
\begin{funcdesc}{group}{\optional{g1, g2, ...}}
Returns one or more groups of the match. If there is a single
\var{index} argument, the result is a single string; if there are
@@ -525,6 +498,14 @@ such group exists, the corresponding result is
If the regular expression uses the \code{(?P<\var{name}>...)} syntax,
the \var{index} arguments may also be strings identifying groups by
their group name.
+
+A moderately complicated example:
+\bcode\begin{verbatim}
+m = re.match(r"(?P<int>\d+)\.(\d*)", '3.14')
+\end{verbatim}\ecode
+%
+After performing this match, \code{m.group(1)} is \code{'3'}, as is \code{m.group('int')}.
+\code{m.group(2)} is \code{'14'}.
\end{funcdesc}
\begin{funcdesc}{groups}{}
@@ -534,6 +515,34 @@ participate in the match have values of \code{None}. If the tuple
would only be one element long, a string will be returned instead.
\end{funcdesc}
+\begin{funcdesc}{start}{group}
+\end{funcdesc}
+
+\begin{funcdesc}{end}{group}
+Return the indices of the start and end of the substring
+matched by \var{group}. Return \code{None} if \var{group} exists but
+did not contribute to the match. For a match object
+\code{m}, and a group \code{g} that did contribute to the match, the
+substring matched by group \code{g} (equivalent to \code{m.group(g)}) is
+\bcode\begin{verbatim}
+ m.string[m.start(g):m.end(g)]
+\end{verbatim}\ecode
+%
+Note that
+\code{m.start(\var{group})} will equal \code{m.end(\var{group})} if
+\var{group} matched a null string. For example, after \code{m =
+re.search('b(c?)', 'cba')}, \code{m.start(0)} is 1, \code{m.end(0)} is
+2, \code{m.start(1)} and \code{m.end(1)} are both 2, and
+\code{m.start(2)} raises an \code{IndexError} exception.
+
+\end{funcdesc}
+
+\begin{funcdesc}{span}{group}
+Return the 2-tuple \code{(start(\var{group}), end(\var{group}))}.
+Note that if \var{group} did not contribute to the match, this is
+\code{(None, None)}.
+\end{funcdesc}
+
\begin{datadesc}{pos}
The value of \var{pos} which was passed to the
\code{search} or \code{match} function. This is the index into the
@@ -556,5 +565,10 @@ The string passed to \code{match()} or \code{search()}.
\end{datadesc}
\begin{seealso}
-\seetext Jeffrey Friedl, \emph{Mastering Regular Expressions}.
+\seetext Jeffrey Friedl, \emph{Mastering Regular Expressions},
+O'Reilly. The Python material in this book dates from before the re
+module, but it covers writing good regular expression patterns in
+great detail.
\end{seealso}
+
+