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<h3>
Flat Databases</h3>
<p>The simplest way to store any kind of information in Python is using flat files. You just need to use the <tT CLAss="monofont">open</tt> function that we already studied in <A HREf="22.html">Chapter 2, "Language Review."
</a> Two options are available: You can either store the information as simple text or as binary data.</p>
<h4>
Text Data</H4>
<P>The next example is a straightforward case of using flat files to store and to retrieve information. First we try to read from the file. If the file doesn't exist, it is created, and the information provided by the user is saved on it.</P>
<Pre>
filename = "myflatfile.txt"
try:
file = open(filename, "r")
data = file.read()
file.close()
print data
except IOError:
data = raw_input("Enter data to save:")
file = open(filename,"w")
file.write(data)
file.close()
</pre>
<h4>
Binary Data桾he <tt class="monofont">struct</tt> Module</h4>
<p>The <tt cLasS="monofont">struct</tt> module is largely used to manipulate code of platform-independent binary files. It is a good choice for handling small files. For large files, you should consider using the <a Name="idx1073744834"></a>
<A namE="idx1073744835"></A>
<TT clasS="monofont">array</TT> module.</P>
<p>Binary data files are much less likely to be platform independent. Also, it is easier to extend a text file format without breaking compatibility.</p>
<p>The <tT CLAss="monofont">struct</tt> module works by converting data between Python and binary data structures, which normally interact using functions written in C.</P>
<P>This module implements only three functions: <TT class="monofont">pack, unpack,</tt> and <tt class="monofont">calcsize.</tt>
</p>
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