sam-t2/devtools/v8plus/html/python/lib/matching-searching.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<link rel="STYLESHEET" href="lib.css" type='text/css' />
<link rel="SHORTCUT ICON" href="../icons/pyfav.png" type="image/png" />
<link rel='start' href='../index.html' title='Python Documentation Index' />
<link rel="first" href="lib.html" title='Python Library Reference' />
<link rel='contents' href='contents.html' title="Contents" />
<link rel='index' href='genindex.html' title='Index' />
<link rel='last' href='about.html' title='About this document...' />
<link rel='help' href='about.html' title='About this document...' />
<link rel="next" href="node115.html" />
<link rel="prev" href="re-syntax.html" />
<link rel="parent" href="module-re.html" />
<link rel="next" href="node115.html" />
<meta name='aesop' content='information' />
<title>4.2.2 Matching vs Searching </title>
</head>
<body>
<DIV CLASS="navigation">
<div id='top-navigation-panel' xml:id='top-navigation-panel'>
<table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td class='online-navigation'><a rel="prev" title="4.2.1 Regular Expression Syntax"
  href="re-syntax.html"><img src='../icons/previous.png'
  border='0' height='32'  alt='Previous Page' width='32' /></A></td>
<td class='online-navigation'><a rel="parent" title="4.2 re  "
  href="module-re.html"><img src='../icons/up.png'
  border='0' height='32'  alt='Up One Level' width='32' /></A></td>
<td class='online-navigation'><a rel="next" title="4.2.3 Module Contents"
  href="node115.html"><img src='../icons/next.png'
  border='0' height='32'  alt='Next Page' width='32' /></A></td>
<td align="center" width="100%">Python Library Reference</td>
<td class='online-navigation'><a rel="contents" title="Table of Contents"
  href="contents.html"><img src='../icons/contents.png'
  border='0' height='32'  alt='Contents' width='32' /></A></td>
<td class='online-navigation'><a href="modindex.html" title="Module Index"><img src='../icons/modules.png'
  border='0' height='32'  alt='Module Index' width='32' /></a></td>
<td class='online-navigation'><a rel="index" title="Index"
  href="genindex.html"><img src='../icons/index.png'
  border='0' height='32'  alt='Index' width='32' /></A></td>
</tr></table>
<div class='online-navigation'>
<b class="navlabel">Previous:</b>
<a class="sectref" rel="prev" href="re-syntax.html">4.2.1 Regular Expression Syntax</A>
<b class="navlabel">Up:</b>
<a class="sectref" rel="parent" href="module-re.html">4.2 re  </A>
<b class="navlabel">Next:</b>
<a class="sectref" rel="next" href="node115.html">4.2.3 Module Contents</A>
</div>
<hr /></div>
</DIV>
<!--End of Navigation Panel-->

<H2><A NAME="SECTION006220000000000000000"></A><A NAME="matching-searching"></A>
<BR>
4.2.2 Matching vs Searching
</H2>

<P>
Python offers two different primitive operations based on regular
expressions: match and search.  If you are accustomed to Perl's
semantics, the search operation is what you're looking for.  See the
<tt class="function">search()</tt> function and corresponding method of compiled
regular expression objects.

<P>
Note that match may differ from search using a regular expression
beginning with "<tt class="character">^</tt>":
"<tt class="character">^</tt>" matches only at the
start of the string, or in <tt class="constant">MULTILINE</tt> mode also immediately
following a newline.  The ``match'' operation succeeds only if the
pattern matches at the start of the string regardless of mode, or at
the starting position given by the optional <var>pos</var> argument
regardless of whether a newline precedes it.

<P>
<div class="verbatim"><pre>
re.compile("a").match("ba", 1)           # succeeds
re.compile("^a").search("ba", 1)         # fails; 'a' not at start
re.compile("^a").search("\na", 1)        # fails; 'a' not at start
re.compile("^a", re.M).search("\na", 1)  # succeeds
re.compile("^a", re.M).search("ba", 1)   # fails; no preceding \n
</pre></div>

<P>

<DIV CLASS="navigation">
<div class='online-navigation'>
<p></p><hr />
<table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td class='online-navigation'><a rel="prev" title="4.2.1 Regular Expression Syntax"
  href="re-syntax.html"><img src='../icons/previous.png'
  border='0' height='32'  alt='Previous Page' width='32' /></A></td>
<td class='online-navigation'><a rel="parent" title="4.2 re  "
  href="module-re.html"><img src='../icons/up.png'
  border='0' height='32'  alt='Up One Level' width='32' /></A></td>
<td class='online-navigation'><a rel="next" title="4.2.3 Module Contents"
  href="node115.html"><img src='../icons/next.png'
  border='0' height='32'  alt='Next Page' width='32' /></A></td>
<td align="center" width="100%">Python Library Reference</td>
<td class='online-navigation'><a rel="contents" title="Table of Contents"
  href="contents.html"><img src='../icons/contents.png'
  border='0' height='32'  alt='Contents' width='32' /></A></td>
<td class='online-navigation'><a href="modindex.html" title="Module Index"><img src='../icons/modules.png'
  border='0' height='32'  alt='Module Index' width='32' /></a></td>
<td class='online-navigation'><a rel="index" title="Index"
  href="genindex.html"><img src='../icons/index.png'
  border='0' height='32'  alt='Index' width='32' /></A></td>
</tr></table>
<div class='online-navigation'>
<b class="navlabel">Previous:</b>
<a class="sectref" rel="prev" href="re-syntax.html">4.2.1 Regular Expression Syntax</A>
<b class="navlabel">Up:</b>
<a class="sectref" rel="parent" href="module-re.html">4.2 re  </A>
<b class="navlabel">Next:</b>
<a class="sectref" rel="next" href="node115.html">4.2.3 Module Contents</A>
</div>
</div>
<hr />
<span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span>
</DIV>
<!--End of Navigation Panel-->
<ADDRESS>
See <i><a href="about.html">About this document...</a></i> for information on suggesting changes.
</ADDRESS>
</BODY>
</HTML>