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php遍历树的常用方法汇总

来源:互联网  作者:网友投稿  发布时间:2021-01-04 01:00
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...

一、递归的深度优先的算法:

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<?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)

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<?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)

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<?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");

?>

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php遍历树的常用方法汇总

2021-01-04 编辑:网友投稿

一、递归的深度优先的算法:

?

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

 

<?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)

?

1

2

3

4

5

6

7

8

9

10

11

12

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14

15

16

17

18

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33

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35

36

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40

41

42

43

44

 

<?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)

?

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<?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");

?>

本站内容来源于网络,如有侵权请与我们联系,我们会及时删除,我们深感抱歉!
注:本站所有信息仅供学习参考!
本文地址为 https://v30.fanwenzhu.com/jiaob/php/10899.shtml

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