Example of using PHP recursive functions

PHP recursive function in our actual development is not a small part, for programmers, PHP recursive function roommate very high value, can solve a lot of problems, today we will introduce you to PHP recursive function use example!

This article mainly introduces the PHP recursive use example (PHP recursive function), including recursion to get the role ID string, recursively get the Cascade role information array, through the ID of the parent role to obtain child role information, the need for friends can refer to the next

Recursively get the Role ID string function Exploderole ($ROLEOBJ, & $resultStr) {if (0 < count ($roleObj->childroleobjarr)) { foreach ($roleObj->childroleobjarr as $CHILDROLEOBJ) {if (' = = $resultStr) {$resultStr. = "{$CHILDROLEOBJ-&G      T;id} ";      }else{$resultStr. = ", {$childRoleObj->id}";    } exploderole ($CHILDROLEOBJ, $RESULTSTR); }}//recursively gets the cascading role information array function makerolerelation (& $ROLEOBJARR) {foreach ($roleObjArr as $item) {$item->childroleobj    ARR = Getroleobjarrbyparentid ($item->id);    if (0 < count ($item->childroleobjarr)) {makerolerelation ($item->childroleobjarr);  }}//Gets the child role information through the ID of the parent role function Getroleobjarrbyparentid ($parentid) {$operCOGPSTRTSysRole = new cogpstrtsysrole ();  $operCOGPSTRTSysRole->setcolumn ($operCOGPSTRTSysRole->getallcolumn ());  $operCOGPSTRTSysRole->setwhere ("parentroleid={$parentid}");  $ROLEOBJARR = $operCOGPSTRTSysRole->convresult2objarr ($operCOGPSTRTSysRole->selecttable ()); return Isset ($rOleobjarr)? $ROLEOBJARR: Array ();} 

Recursive function Usage for PHP

A function calls itself in its function body called a recursive call. This function is called a recursive function. This is usually a high practical value for programmers, often used to break down complex problems into simple and identical situations, and do this repeatedly until the problem is solved.

The difference between recursive function and no recursive function

Example one: using static variables

function test () {  static $dig =0;  if ($dig ++<10) {    echo $dig;    Test ();}  } Test ();//12345678910

Example two: Using recursive functions and loops to implement string reversal permutations

function Unreverse ($str) {  for ($i =1; $i <=strlen ($STR); $i + +) {    echo substr ($str,-$i, 1);  }} Unreverse ("ABCDEFG");//gfedcbcfunction reverse ($str) {  if (strlen ($STR) >0) {    reverse (substr ($STR, 1));    Echo substr ($STR, 0,1);    return;}  } Reverse ("ABCDEFG");//GFEDCBC

Recursive functions many times we can recycle, suggesting that we don't use loops instead, because we're easier to understand with loops, and less prone to mistakes.

PHP Recursive functions PHP pay recursive functions, recursive functions are called themselves, these functions are particularly useful for browsing dynamic data structures, such as trees and lists.
Few Web applications require complex data structures to be used

<?phpfunction Reversr_r ($STR) {if (strlen ($STR) >0) Reverse_r (substr ($STR, 1)); Echo substr ($STR, 0,1); return;}? ><?phpfunction reverse_i ($STR) {for ($i =1; $i <=strlen ($STR); $i + +) {echo substr ($str,-$i, 1);}}

This program manifest implements two functions, both of which can print the contents of a string in reverse order
The function Reversr_r is implemented recursively, and the function reverse_i () is implemented through loops.

Summarize:

This article uses two examples to resolve the use of PHP recursive functions, the small partners can through this article on the PHP recursive function has a substantial understanding!

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