php遍历树的常用方法汇总
发布:smiling 来源: PHP粉丝网 添加日期:2021-05-28 21:29:58 浏览: 评论:0
这篇文章主要介绍了php遍历树的常用方法,实例分析了php常用的三种遍历树的技巧,需要的朋友可以参考下,本文实例讲述了php遍历树的常用方法,分享给大家供大家参考,具体如下:
一、递归的深度优先的算法:
- <?php
- define('DS', DIRECTORY_SEPARATOR);
- function rec_list_files($from = '.')
- {
- if(!is_dir($from)) {
- return array();
- }
- $files = array();
- if($dh = opendir($from))
- {
- while(false !== ($file = readdir($dh))) {
- if($file == '.' || $file == '..') {
- continue;
- }
- $path = $from . DS . $file;
- if (is_file($path)) {
- $files[] = $path;
- }
- $files = array_merge($files, rec_list_files($path));
- }
- closedir($dh);
- }
- return $files;
- }
- function profile($func, $trydir)
- {
- $mem1 = memory_get_usage();
- echo '<pre>----------------------- Test run for '.$func.'() ';
- flush();
- $time_start = microtime(true);
- $list = $func($trydir);
- //print_r($list);
- $time = microtime(true) - $time_start;
- echo 'Finished : '.count($list).' files</pre>';
- $mem2 = memory_get_peak_usage();
- printf('<pre>Max memory for '.$func.'() : %0.2f kbytes Running time for '.$func.'() : %0.f s</pre>',
- ($mem2-$mem1)/1024.0, $time);
- return $list;
- }
- profile('rec_list_files', "D:\www\server");
- ?>
二、递归的深度优先的算法(用了一个栈来实现)
- <?php
- define('DS', DIRECTORY_SEPARATOR);
- function deep_first_list_files($from = '.')
- {
- if(!is_dir($from)) {
- return false;
- }
- $files = array();
- $dirs = array($from);
- while(NULL !== ($dir = array_pop($dirs))) {
- if( $dh = opendir($dir)) {
- while( false !== ($file = readdir($dh))) {
- if($file == '.' || $file == '..') {
- continue;
- }
- $path = $dir . DS . $file;
- if(is_dir($path)) {
- $dirs[] = $path;
- } else {
- $files[] = $path;
- }
- }
- closedir($dh);
- }
- }
- return $files;
- }
- function profile($func, $trydir)
- {
- $mem1 = memory_get_usage();
- echo '<pre>----------------------- Test run for '.$func.'() ';
- flush();
- $time_start = microtime(true);
- $list = $func($trydir);
- //print_r($list);
- $time = microtime(true) - $time_start;
- echo 'Finished : '.count($list).' files</pre>';
- $mem2 = memory_get_peak_usage();
- printf('<pre>Max memory for '.$func.'() : %0.2f kbytes Running time for '.$func.'() : %0.f s</pre>',
- ($mem2-$mem1)/1024.0, $time);
- return $list;
- }
- profile('deep_first_list_files', "D:\www\server");
- ?>
三、非递归的广度优先算法(用了一个队列来实现)
- <?php
- define('DS', DIRECTORY_SEPARATOR);
- function breadth_first_files($from = '.') {
- $queue = array(rtrim($from, DS).DS);// normalize all paths
- $files = array();
- while($base = array_shift($queue )) {
- if (($handle = opendir($base))) {
- while (($child = readdir($handle)) !== false) {
- if( $child == '.' || $child == '..') {
- continue;
- }
- if (is_dir($base.$child)) {
- $combined_path = $base.$child.DS;
- array_push($queue, $combined_path);
- } else {
- $files[] = $base.$child;
- }
- }
- closedir($handle);
- } // else unable to open directory => NEXT CHILD
- }
- return $files; // end of tree, file not found
- }
- function profile($func, $trydir)
- {
- $mem1 = memory_get_usage();
- echo '<pre>----------------------- Test run for '.$func.'() ';
- flush();
- $time_start = microtime(true);
- $list = $func($trydir);
- //print_r($list);
- $time = microtime(true) - $time_start;
- echo 'Finished : '.count($list).' files</pre>';
- $mem2 = memory_get_peak_usage();
- printf('<pre>Max memory for '.$func.'() : %0.2f kbytes Running time for '.$func.'() : %0.f s</pre>',
- ($mem2-$mem1)/1024.0, $time);
- return $list;
- }
- profile('breadth_first_files', "D:\www\server");
- ?>
Tags: php遍历树
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