This time I will bring you php recursive functiondetailed explanation of case usage, php recursivefunction caseWhat are the precautions used, the following is a practical case, Let’s take a look.
Regarding the usage of PHP recursive functions, share a few examples of PHP recursive functions. In PHP programming, it is very common to use recursion to make function calls. Recursive functions can be used well to improve code efficiency. Learn PHP through examples. Use of recursive functions.
1. What is a recursive function?
A function calling itself within its function body is called a recursive call. This kind of function is called a recursive function.
What is the difference between recursive functions and non-recursive functions in php?
Example 1: Using static variables
Code example:
function test(){ static $dig=0; if($dig++<p style="text-align: left;">Example 2: Using recursive functions and loops to implement <a href="http://www.php.cn/wiki/57.html" target="_blank">String</a>Reverse arrangement</p> <p style="text-align: left;">Code example:</p><pre class="brush:php;toolbar:false">function unreverse($str){ for($i=1;$i0){ reverse(substr($str,1)); echo substr($str,0,1); return; } } reverse("abcdefg");//gfedcbc
2. PHP recursive function usage example
php recursionUsage example(php Recursive function), including recursively obtaining the role ID string, recursively obtaining the cascade role information array, and obtaining child role information through the id of the parent role.
Example:
Code example:
//递归获得角色ID字符串 function explodeRole($roleObj, &$resultStr){ if(0 childRoleObjArr)){ foreach($roleObj->childRoleObjArr as $childRoleObj){ if('' == $resultStr){ $resultStr .= "{$childRoleObj->id}"; }else{ $resultStr .= ", {$childRoleObj->id}"; } explodeRole($childRoleObj, $resultStr); } } } //递归获取级联角色信息数组 function makeRoleRelation(&$roleObjArr){ foreach($roleObjArr as $item){ $item->childRoleObjArr = getRoleObjArrByParentId($item->id); if(0 childRoleObjArr)){ makeRoleRelation($item->childRoleObjArr); } } } //通过父角色的id获取子角色信息 function getRoleObjArrByParentId($parentid){ $operCOGPSTRTSysRole = new COGPSTRTSysRole(); $operCOGPSTRTSysRole->setColumn($operCOGPSTRTSysRole->getAllColumn()); $operCOGPSTRTSysRole->setWhere("parentroleid={$parentid}"); $roleObjArr = $operCOGPSTRTSysRole->convResult2ObjArr($operCOGPSTRTSysRole->selectTable()); return isset($roleObjArr)?$roleObjArr:array(); }
php recursive function usage
Example 1: Use Static variables implement recursion.
Code example:
function test(){ static $dig=0; if($dig++<p style="text-align: left;">Example 2: Use recursive functions and loops to achieve string reversal. </p><p style="text-align: left;">Code example:</p><pre class="brush:php;toolbar:false">function unreverse($str){ for($i=1;$i0){ reverse(substr($str,1)); echo substr($str,0,1); return; } } reverse("abcdefg");//gfedcbc
PHP recursive functions can sometimes be replaced by loops. It is recommended to use them when loops cannot be used, because it is easier for us to understand and less error-prone with loops. PHP recursive functions PHP pays recursive functions. Recursive functions call themselves. These functions are particularly suitable for browsing dynamic data structures, such as trees and lists. Few web applications require the use of complex data structures.
Example:
Code example:
reverse_r(substr($str,1)); echo substr($str,0,1); return; } ?>
This program list implements two functions, both of which can print the contents of a string in reverse order. The function reversr_r is It is implemented through recursion, and the function reverse_i() is implemented through loops.
I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!
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The above is the detailed content of Detailed explanation of the use of php recursive function cases. For more information, please follow other related articles on the PHP Chinese website!

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

在PHP中,可以利用implode()函数的第一个参数来设置没有分隔符,该函数的第一个参数用于规定数组元素之间放置的内容,默认是空字符串,也可将第一个参数设置为空,语法为“implode(数组)”或者“implode("",数组)”。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。


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