An example of an infinite loop array (recursion)

/**
* Author : GuoWangYunYan
* QQ : 279861795
* Date : 2011-6-23
* link：www.jbuxe.com
*/
//Set encoding
header('Content-type: text/html; charset=utf-8');
/ /In a weird way, I used a five-dimensional array
$a = array(
 'AAAAAA' => array(
 'aaaaaa' => array(
 '111111',
 '222222',
 '333333'
 ) ,
 'bbbbbb' => array(
 '111111',
 '222222',
 '333333'
 ),
 'cccccc' => array(
 '111111',
 '222222',
 '333333'
 ),
 ),
 'BBBBBB' => array(
 'aaaaaa' => array(
 '111111',
 '222222',
 '333333'
 ),
 'bbbbbb' => array(
 '111111',
 '222222',
 '333333'
 ),
 'cccccc'=> array(
 '111111',
 '222222',
 '333333'
 ),
 ),
 'CCCCCC' => array(
 'aaaaaa'=> array(
 '111111',
 '222222',
 '333333'
 ),
 'bbbbbb' => array(
 '111111',
 '222222',
 '333333'
 ),
 'cccccc' => array(
 '111111'=>array('44','55','66'),
 '222222'=>array('44' ,'55','66'),
 '333333'=>array(
 '44'=>array('77','88','99'),
 '55'=>array( '77','88','99'),
 '66'=>array('77','88','99'),
 ),
 ),
 ),
);
//Execute function
 fun($a);

 //The infinite classification recursion method begins
 function fun ($_info,$deep=0){
 //Judge whether it is an array
 if ( is_array($_info)){
 //foreach loop
 foreach ($_info as $key=>$val){
 //The first time before - no more each time the loop adds 4 by the way to output the key name
 echo str_repeat (' - ',$deep).$key.'';
 //Recursively output the key value and add 4 in front each time----
 fun($val,$deep+4) ;
 }
 } else {
 //If the key value is not an array, return directly
 echo str_repeat('-', $deep) . "$val";
 }
 }
?>< /p>

Recursive explanation: Recursion, as an algorithm, is widely used in programming languages. It refers to the reentrancy phenomenon caused by a function/process/subprogram calling itself directly or indirectly during operation. Recursion is an important concept in computer science. The recursive method is an effective method in programming. Writing programs using recursion can make the program concise and clear.

If recursion is not used, the execution efficiency is relatively low.