1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Why doesn't my *= operator work?</title> 5<link rel="stylesheet" href="../boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../index.html" title="Boost.Python"> 8<link rel="up" href="../faq.html" title="Chapter 5. Frequently Asked Questions (FAQs)"> 9<link rel="prev" href="how_do_i_debug_my_python_extensi.html" title="How do I debug my Python extensions?"> 10<link rel="next" href="does_boost_python_work_with_mac_.html" title="Does Boost.Python work with Mac OS X?"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="" width="" height="" src="../images/boost.png"></td></tr></table> 14<hr> 15<div class="spirit-nav"> 16<a accesskey="p" href="how_do_i_debug_my_python_extensi.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../faq.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="does_boost_python_work_with_mac_.html"><img src="../images/next.png" alt="Next"></a> 17</div> 18<div class="section"> 19<div class="titlepage"><div><div><h3 class="title"> 20<a name="faq.why_doesn_t_my_operator_work"></a><a class="link" href="why_doesn_t_my_operator_work.html" title="Why doesn't my *= operator work?">Why doesn't my <code class="computeroutput"><span class="special">*=</span></code> operator work?</a> 21</h3></div></div></div> 22<p> 23 <span class="bold"><strong>Q:</strong></span> <span class="emphasis"><em>I have exported my class to 24 python, with many overloaded operators. it works fine for me except the 25 <code class="computeroutput"><span class="special">*=</span></code> operator. It always tells 26 me "can't multiply sequence with non int type". If I use <code class="computeroutput"><span class="identifier">p1</span><span class="special">.</span><span class="identifier">__imul__</span><span class="special">(</span><span class="identifier">p2</span><span class="special">)</span></code> 27 instead of <code class="computeroutput"><span class="identifier">p1</span> <span class="special">*=</span> 28 <span class="identifier">p2</span></code>, it successfully executes my 29 code. What's wrong with me?</em></span> 30 </p> 31<p> 32 <span class="bold"><strong>A:</strong></span> There's nothing wrong with you. This 33 is a bug in Python 2.2. You can see the same effect in Pure Python (you can 34 learn a lot about what's happening in Boost.Python by playing with new-style 35 classes in Pure Python). 36 </p> 37<pre class="programlisting"><span class="special">>>></span> <span class="keyword">class</span> <span class="identifier">X</span><span class="special">(</span><span class="identifier">object</span><span class="special">):</span> 38<span class="special">...</span> <span class="identifier">def</span> <span class="identifier">__imul__</span><span class="special">(</span><span class="identifier">self</span><span class="special">,</span> <span class="identifier">x</span><span class="special">):</span> 39<span class="special">...</span> <span class="identifier">print</span> <span class="char">'imul'</span> 40<span class="special">...</span> 41<span class="special">>>></span> <span class="identifier">x</span> <span class="special">=</span> <span class="identifier">X</span><span class="special">()</span> 42<span class="special">>>></span> <span class="identifier">x</span> <span class="special">*=</span> <span class="number">1</span> 43</pre> 44<p> 45 To cure this problem, all you need to do is upgrade your Python to version 46 2.2.1 or later. 47 </p> 48</div> 49<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 50<td align="left"></td> 51<td align="right"><div class="copyright-footer">Copyright © 2002-2015 David 52 Abrahams, Stefan Seefeld<p> 53 Distributed under the Boost Software License, Version 1.0. (See accompanying 54 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 55 </p> 56</div></td> 57</tr></table> 58<hr> 59<div class="spirit-nav"> 60<a accesskey="p" href="how_do_i_debug_my_python_extensi.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../faq.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="does_boost_python_work_with_mac_.html"><img src="../images/next.png" alt="Next"></a> 61</div> 62</body> 63</html> 64
