PHP anonymous function using skills

I wrote a previous article about the use of closures( Click here to enter ), this in-depth summary of the usage and understanding of anonymous functions in php:

Anonymous functions in php, also called closure functions, allow you to specify a function without a name. Assign anonymous functions to variables and call them through variables. For example:

<?php
$anonymousFunc = function($username){
    echo $username;
  };
$anonymousFunc("Qiao Feng!");

Tip 1: put the anonymous function in the ordinary function, or return the anonymous function, which forms a simple closure

<?php
function closureFunc(){
    $anonymousFunc = function(){
        echo "Qiao Feng!";
    };
    $anonymousFunc();//Anonymous function called inside normal function
}
closureFunc();//output: Qiao Feng

Tip 2: reference local variables in anonymous functions (here you need to refer to a php keyword use)

<?php

function closureFunc(){
    $username = 'Qiao Feng';
    $anonymousFunc = function() use($username){
        echo $username;
    };
    $anonymousFunc();//Anonymous function called here
}
closureFunc();//output: Qiao Feng

Skill 3: return anonymous function in normal function

<?php

function closureFunc(){
    $username = 'Qiao Feng';
    $anonymousFunc = function() use($username){
        echo $username;
    };
    return $anonymousFunc;// Function returns an anonymous function
}
$func = closureFunc();
$func(); //Then call $func()

4 return anonymous function and pass parameter to anonymous function

<?php

function closureFunc(){
    $username = 'Qiao Feng';
    $anonymousFunc = function($lover,$skill) use($username){
        echo $username.$lover.$skill;
    };
    return $anonymousFunc;
}
$func = closureFunc();
$func("Arzhu","Dragons");//Qiao Feng, a Zhu, dragon catcher

5 use closure to change the variable value of context reference

<?php

function closureFunc(){
    $number = 100;
    $anonymousFunc = function() use($number) {
        $number++;
        echo $number.PHP_EOL;
    };
    echo $number.PHP_EOL;
    return $anonymousFunc;
}
$func = closureFunc();// Output 1 here, directly calling the echo $number.PHP_EOL; That is 100
$func();// Return value of calling function $anonymousFunc  $number++ That is 101
$func(); //101
$func();//101

In the above input result, it is found that the following two FuncS () return 101, and the value has not changed. If you want to accumulate the + + effect, you only need to add a & reference symbol (changes in anonymous functions will also affect external variables). Modify the following:

<?php

function closureFunc(){
    $number = 100;
    $anonymousFunc = function() use(&$number) {
        $number++;
        echo $number.PHP_EOL;
    };
    echo $number.PHP_EOL;
    return $anonymousFunc;
}
$func = closureFunc();// Output 1 here, directly calling the echo $number.PHP_EOL; That is 100
$func();// Return value of calling function $anonymousFunc  $number++ That is 101
$func(); //102
$func();//103

Tip 6: pass anonymous functions as parameters

<?php
//Define common functions, anonymousFunc Is a parameter variable
function myFunc($anonymousFunc){
    $anonymousFunc("Qiao Feng");
}

myFunc(function($username){ //Here we call ordinary functions and pass anonymous functions as parameters to myFunc Medium $anonymousFunc
    echo $username;
});//Output Qiaofeng

At present, this is all you need to do. Welcome to add...

Keywords: PHP

Added by monkeytooth on Sun, 08 Dec 2019 10:17:55 +0200

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PHP anonymous function using skills

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