Advanced explanation of php functions

Use variables to store function names, and write them in the form of variables () when calling. This article mainly shares with you the advanced explanation of PHP functions, I hope it can help you.

Applicable situations:

Used when calling different functions according to the type of user feedback information.
Example:

$funf = 'test';
$funf();

Internal function call function external variable

Use usekeyword

Example

function test(){
    $msg = "I'm message.";
    // 使用use关键字，获取变量
    $say = function($str) use(&$msg){
        echo $msg;  
        echo &#39;<hr/>&#39;;     
        echo $str;
    };
    $say(&#39;Hello World&#39;);
}
test();

Bubble sort

The so-called bubble sort is to throw the array parameters from small to large or from large to small.

Example:

// 从小到大例子
//定义一个数组
$arr = [1,3,2,10,8,7,9];
// 冒泡排序主函数
function sortArr($arr){
    // 进行外层遍历，其实就是规定循环多少次
    for($i=0; $i<count($arr); $i++) {
        // 从第i+1个参数开始遍历，同样遍历那么多次
        for ($j=$i+1; $j<count($arr); $j++) {
            // 比较内外层的数
            if($arr[$i] > $arr[$j]){
                // 内层的值赋值给临时变量
                $temp = $arr[$j];
                // 交换位置
                $arr[$j] = $arr[$i];
                // 再从临时变量中赋值回来
                $arr[$i] = $temp;
            }
        }
    }
  // 返回排序后的数组
  return $arr;
}
print_r(sortArr($arr));

Reference materials:

Related recommendations:

Advanced learning of JavaScript functions Detailed explanation of advanced function example code

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