<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Introduction</title> </head> <body><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="book.judy.html">Judy</a></div> <div class="next" style="text-align: right; float: right;"><a href="judy.setup.html">Installing/Configuring</a></div> <div class="up"><a href="book.judy.html">Judy</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div><hr /><div id="intro.judy" class="preface"> <h1 class="title">Introduction</h1> <p class="para"> <acronym title="PHP: Hypertext Preprocessor">PHP</acronym> Judy is a <acronym title="PHP Extension and Application Repository">PECL</acronym> extension for the <a href="http://judy.sourceforge.net" class="link external">» Judy C library</a> implementing dynamic sparse arrays. </p> <p class="para"> A Judy array is a complex but very fast associative array data structure for storing and looking up values using integer or string keys. Unlike normal arrays, Judy arrays may be sparse; that is, they may have large ranges of unassigned indices. </p> <p class="para"> A Judy array consumes memory only when populated yet can grow to take advantage of all available memory. Judy's key benefits are: scalability, performance, memory efficiency, and ease of use. Judy arrays are designed to grow without tuning into the peta-element range, scaling near O(log-base-256) -- 1 more RAM access at 256 X population. </p> </div><hr /><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="book.judy.html">Judy</a></div> <div class="next" style="text-align: right; float: right;"><a href="judy.setup.html">Installing/Configuring</a></div> <div class="up"><a href="book.judy.html">Judy</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div></body></html>
