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<H1><A NAME="SECTION007700000000000000000"> </A>
<BR>
5.7 Shifting operations
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<P>
The shifting operations have lower priority than the arithmetic
operations:
<P>
<dl><dd class="grammar">
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<td><code><a name="tok-shift_expr">shift_expr</a></code></td>
<td> ::= </td>
<td><code><a href="binary.html#tok-a_expr">a_expr</a>
| <a href="node58.html#tok-shift_expr">shift_expr</a> ( "«" | "»" ) <a href="binary.html#tok-a_expr">a_expr</a></code></td></tr>
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<a class="grammar-footer"
href="grammar.txt" type="text/plain"
>Download entire grammar as text.</a>
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<P>
These operators accept plain or long integers as arguments. The
arguments are converted to a common type. They shift the first
argument to the left or right by the number of bits given by the
second argument.
<P>
A right shift by <var>n</var> bits is defined as division by
<code>pow(2,<var>n</var>)</code>. A left shift by <var>n</var> bits is defined as
multiplication with <code>pow(2,<var>n</var>)</code>; for plain integers there is
no overflow check so in that case the operation drops bits and flips
the sign if the result is not less than <code>pow(2,31)</code> in absolute
value. Negative shift counts raise a <tt class="exception">ValueError</tt>
exception.
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<span class="release-info">Release 2.2, documentation updated on December 21, 2001.</span>
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