PHP recursive usage and recursive directory instance _php tutorial

Recursive algorithm in PHP is not much of our data traversal method, let me introduce you to the use of recursion to do something.

See a simple recursive instance

Example 1

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function Demo ($a) { static $sum = 1; if ($a > 1) { $sum *= $a; Demo (--$a); }else{ $a = $sum; } return $sum; } Echo Demo (10);

Example 2

Traverse Directory

The code is as follows

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Class listdir{ var $depth; var $dirname; var $list; var $tostring; function Listdir ($dir) { $this->dirname= $dir; $this->depth=0; $this->tostring= ""; } Save the result in a multidimensional array function getlist ($dir = "") { if ($dir = = "") $dir = $this->dirname; $d = @dir ($dir); while (false!== ($item = $d->read ())) { if ($item! = "." && $item! = "...") { $path = $dir. " /". $item; if (Is_dir ($path)) { $this->depth+=1; $this->getlist ($path); }else{ $this->list[$this->depth][]= $item; } } } $this->list[$this->depth][' directory ']= $dir; $this->depth-=1; $d->close (); return $this->list; } Character channeling results function ToString ($dir = "") { if ($dir = = "") $dir = $this->dirname; $d = @dir ($dir); $this->tostring.= " n "; $this->tostring.= "Directory:" $dir. " n "; while (false!== ($item = $d->read ())) { if ($item! = "." && $item! = "...") { $path = $dir. " /". $item; if (Is_dir ($path)) { $this->depth+=1; $this->tostring ($path); }else{ $this->tostring.= " ". $item." n "; } } } $this->depth-=1; $d->close (); $this->tostring.= " n "; return $this->tostring; } } $wapdir = "jquery"; $d =new Listdir ($wapdir); echo $d->tostring (); ?> Output Result: Directory:jquery Jquery-1.3.2.js Jquery-1.3.2.min.js Jquery-1.3.2-vsdoc2.js Test.html Common.js directory:jquery/d Common.js Jquery-1.3.2.js

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