Tips for using anonymous functions in PHP

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Anonymous functions(Anonymous functions) in PHP are also called closure functions(closures), allows specifying a function without a name. The most commonly used one is the parameter value of callback function.

1. Reference local variables in anonymous functions (use the use keyword in PHP here).

<?php
function F1(){

    $ok="HelloWorld";

    $a=function() use($ok) {
        echo "$ok";
    };
    $a();
}
F1();
?>

2. Place the anonymous function in a normal function, or return the anonymous function.

<?php
function F1(){
    $a=function() {
        echo "HelloWorld";
    };
    $a();
}
F1();
?>

3. Return in an ordinary function.

<?php
function F1(){
    $a=function() {
        echo "HelloWorld";
    };
    return $a;
}
$abc=F1();
$abc();
?>

4. Return the anonymous function and pass parameters to the anonymous function.

<?php
function F1(){

    $a=function($name,$do) {
        echo $name." ".$do." HelloWorld";
    };
    return $a;
}
$abc=F1();
$abc(&#39;张三&#39;,&#39;say&#39;);
?>

5. Pass anonymous functions as parameters.

<?php
function F1($UnkownFun){
    $UnkownFun("张三");
}

F1(function ($username){
      echo $username;
});

?>

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