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<H2>
<BR>
2.1.3 Comparisons
</H2>
<P>
Comparison operations are supported by all objects. They all have the
same priority (which is higher than that of the Boolean operations).
Comparisons can be chained arbitrarily; for example, <code><var>x</var> <
<var>y</var> <= <var>z</var></code> is equivalent to <code><var>x</var> < <var>y</var> and
<var>y</var> <= <var>z</var></code>, except that <var>y</var> is evaluated only once (but
in both cases <var>z</var> is not evaluated at all when <code><var>x</var> <
<var>y</var></code> is found to be false).
<P>
This table summarizes the comparison operations:
<P>
<table border align="center" style="border-collapse: collapse">
<thead>
<tr>
<th align="center"><b>Operation</b> </th>
<th align="left"><b>Meaning</b> </th>
<th align="center"><b>Notes</b> </th>
</thead>
<tbody valign='baseline'>
<tr><td align="center" valign="baseline"><code><</code></td>
<td align="left">strictly less than</td>
<td align="center"> </td>
<tr><td align="center" valign="baseline"><code><=</code></td>
<td align="left">less than or equal</td>
<td align="center"> </td>
<tr><td align="center" valign="baseline"><code>></code></td>
<td align="left">strictly greater than</td>
<td align="center"> </td>
<tr><td align="center" valign="baseline"><code>>=</code></td>
<td align="left">greater than or equal</td>
<td align="center"> </td>
<tr><td align="center" valign="baseline"><code>==</code></td>
<td align="left">equal</td>
<td align="center"> </td>
<tr><td align="center" valign="baseline"><code>!=</code></td>
<td align="left">not equal</td>
<td align="center">(1)</td>
<tr><td align="center" valign="baseline"><code><></code></td>
<td align="left">not equal</td>
<td align="center">(1)</td>
<tr><td align="center" valign="baseline"><code>is</code></td>
<td align="left">object identity</td>
<td align="center"> </td>
<tr><td align="center" valign="baseline"><code>is not</code></td>
<td align="left">negated object identity</td>
<td align="center"> </td></tbody>
</table>
<P>
Notes:
<P>
<DL>
<DT><STRONG>(1)</STRONG></DT>
<DD><code><></code> and <code>!=</code> are alternate spellings for the same operator.
(I couldn't choose between ABC and C! :-)
<code>!=</code> is the preferred spelling; <code><></code> is obsolescent.
<P>
</DD>
</DL>
<P>
Objects of different types, except different numeric types, never
compare equal; such objects are ordered consistently but arbitrarily
(so that sorting a heterogeneous array yields a consistent result).
Furthermore, some types (for example, file objects) support only a
degenerate notion of comparison where any two objects of that type are
unequal. Again, such objects are ordered arbitrarily but
consistently.
<P>
Instances of a class normally compare as non-equal unless the class
defines the <tt class="method">__cmp__()</tt> method. Refer to the
<em class='citetitle'><a
href="javascript:if(confirm('http://www.python.org/doc/current/ref/customization.html \n\nThis file was not retrieved by Teleport Pro, because it is addressed on a domain or path outside the boundaries set for its Starting Address. \n\nDo you want to open it from the server?'))window.location='http://www.python.org/doc/current/ref/customization.html'" tppabs="http://www.python.org/doc/current/ref/customization.html"
title='Python Reference Manual'
>Python Reference Manual</a></em> for
information on the use of this method to effect object comparisons.
<P>
<b>Implementation note:</b> Objects of different types except
numbers are ordered by their type names; objects of the same types
that don't support proper comparison are ordered by their address.
<P>
Two more operations with the same syntactic priority,
"<tt class="samp">in</tt>" and "<tt class="samp">not in</tt>", are supported
only by sequence types (below).
<P>
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