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📁 Data Structures And Algorithms With Object-Oriented Design Patterns In Python (2003) source code and

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<HTML><HEAD><TITLE>__init__, __len__ and purge Methods</TITLE></HEAD><BODY bgcolor="#FFFFFF"> <a href="../index.html" target="_top"><img src="../icons/usins.gif" alt="Logo" align=right></a><b>Data Structures and Algorithms with Object-Oriented Design Patterns in Python</b><br><A NAME="tex2html3808" HREF="page227.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="../icons/next_motif.gif"></A> <A NAME="tex2html3806" HREF="page224.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="../icons/up_motif.gif"></A> <A NAME="tex2html3800" HREF="page225.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="../icons/previous_motif.gif"></A>  <A NAME="tex2html3810" HREF="page611.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="../icons/index_motif.gif"></A> <BR><HR><H3><A NAME="SECTION008412000000000000000"><tt>__init__</tt>, <tt>__len__</tt> and <tt>purge</tt> Methods</A></H3><P>The <tt>__init__</tt>, <tt>__len__</tt> and <tt>purge</tt> methodsof the <tt>ChainedHashTable</tt> classare defined in Program&nbsp;<A HREF="page225.html#progchainedHashTablea"><IMG  ALIGN=BOTTOM ALT="gif" SRC="../icons/cross_ref_motif.gif"></A>.In addition to <tt>self</tt>,the <tt>__init__</tt> method takes a single argumentwhich specifies the size of hash table desired.It creates an array of the specified lengthand then initializes the elements of the array.Each element of the array is assigned an empty linked list.The running time for the <tt>ChainedHashTable</tt><tt>__init__</tt> method is <I>O</I>(<I>M</I>) where <I>M</I> is the size of the hash table.<P>The <tt>__len__</tt> method returns the lengthof the <tt>_array</tt> instance attribute.Clearly its running time is <I>O</I>(1)<P>The purpose of the <tt>purge</tt> method is to make the container empty.It does this by invoking the <tt>purge</tt> method one-by-oneon each of the linked lists in the array.The running time of the <tt>purge</tt> method is <I>O</I>(<I>M</I>),where <I>M</I> is the size of the hash table.<P><HR><A NAME="tex2html3808" HREF="page227.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="../icons/next_motif.gif"></A> <A NAME="tex2html3806" HREF="page224.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="../icons/up_motif.gif"></A> <A NAME="tex2html3800" HREF="page225.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="../icons/previous_motif.gif"></A>  <A NAME="tex2html3810" HREF="page611.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="../icons/index_motif.gif"></A> <P><ADDRESS><img src="../icons/bruno.gif" alt="Bruno" align=right><a href="../copyright.html">Copyright &#169; 2003</a> by <a href="../signature.html">Bruno R. Preiss, P.Eng.</a>  All rights reserved.</ADDRESS></BODY></HTML>

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