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<title>2.3.2 Boolean Operations -- and, or, not
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<H2><A NAME=
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2.3.2 Boolean Operations --
<tt class=
"keyword">and
</tt>,
<tt class=
"keyword">or
</tt>,
<tt class=
"keyword">not
</tt>
These are the Boolean operations, ordered by ascending priority:
<a id='l2h-
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<div class=
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"realtable">
<th class=
"center">Operation
</th>
<th class=
"left" >Result
</th>
<th class=
"center">Notes
</th>
<tr><td class=
"center" valign=
"baseline"><code><var>x
</var> or
<var>y
</var></code></td>
<td class=
"left" >if
<var>x
</var> is false, then
<var>y
</var>, else
<var>x
</var></td>
<td class=
"center">(
1)
</td></tr>
<tr><td class=
"center" valign=
"baseline"><code><var>x
</var> and
<var>y
</var></code></td>
<td class=
"left" >if
<var>x
</var> is false, then
<var>x
</var>, else
<var>y
</var></td>
<td class=
"center">(
1)
</td></tr>
<tr><td class=
"center" valign=
"baseline"><code>not
<var>x
</var></code></td>
<td class=
"left" >if
<var>x
</var> is false, then
<code>True
</code>, else
<code>False
</code></td>
<td class=
"center">(
2)
</td></tr></tbody>
<a id='l2h-
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></a><a id='l2h-
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107'
></a>
<DT><STRONG>(
1)
</STRONG></DT>
<DD>These only evaluate their second argument if needed for their outcome.
<DT><STRONG>(
2)
</STRONG></DT>
<DD>"<tt class="samp
">not</tt>" has a lower priority than non-Boolean operators, so
<code>not
<var>a
</var> ==
<var>b
</var></code> is interpreted as
<code>not (
<var>a
</var> ==
<var>b
</var>)
</code>, and
<code><var>a
</var> == not
<var>b
</var></code> is a syntax error.
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<span class=
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2005.
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