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<H2><A NAME="SECTION006440000000000000000"></A><A NAME="differ-examples"></A>
<BR>
4.4.4 Differ Example
</H2>
<P>
This example compares two texts. First we set up the texts, sequences
of individual single-line strings ending with newlines (such sequences
can also be obtained from the <tt class="method">readlines()</tt> method of file-like
objects):
<P>
<div class="verbatim"><pre>
>>> text1 = ''' 1. Beautiful is better than ugly.
... 2. Explicit is better than implicit.
... 3. Simple is better than complex.
... 4. Complex is better than complicated.
... '''.splitlines(1)
>>> len(text1)
4
>>> text1[0][-1]
'\n'
>>> text2 = ''' 1. Beautiful is better than ugly.
... 3. Simple is better than complex.
... 4. Complicated is better than complex.
... 5. Flat is better than nested.
... '''.splitlines(1)
</pre></div>
<P>
Next we instantiate a Differ object:
<P>
<div class="verbatim"><pre>
>>> d = Differ()
</pre></div>
<P>
Note that when instantiating a <tt class="class">Differ</tt> object we may pass
functions to filter out line and character ``junk.'' See the
<tt class="method">Differ()</tt> constructor for details.
<P>
Finally, we compare the two:
<P>
<div class="verbatim"><pre>
>>> result = list(d.compare(text1, text2))
</pre></div>
<P>
<code>result</code> is a list of strings, so let's pretty-print it:
<P>
<div class="verbatim"><pre>
>>> from pprint import pprint
>>> pprint(result)
[' 1. Beautiful is better than ugly.\n',
'- 2. Explicit is better than implicit.\n',
'- 3. Simple is better than complex.\n',
'+ 3. Simple is better than complex.\n',
'? ++ \n',
'- 4. Complex is better than complicated.\n',
'? ^ ---- ^ \n',
'+ 4. Complicated is better than complex.\n',
'? ++++ ^ ^ \n',
'+ 5. Flat is better than nested.\n']
</pre></div>
<P>
As a single multi-line string it looks like this:
<P>
<div class="verbatim"><pre>
>>> import sys
>>> sys.stdout.writelines(result)
1. Beautiful is better than ugly.
- 2. Explicit is better than implicit.
- 3. Simple is better than complex.
+ 3. Simple is better than complex.
? ++
- 4. Complex is better than complicated.
? ^ ---- ^
+ 4. Complicated is better than complex.
? ++++ ^ ^
+ 5. Flat is better than nested.
</pre></div>
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<span class="release-info">Release 2.4.3, documentation updated on 29 March 2006.</span>
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