Anonymous functions and Closure (closure) ____ Functions in PHP

One: anonymous function (can be used in php5.3.0 or above)

The anonymous function (Anonymous functions) in PHP, also called the closure function (closures), allows you to specify a function without a name. The most common is the parameter values of the callback function. (http://php.net/manual/zh/functions.anonymous.php)

 The definition of an anonymous function:

$closureFunc = function () {

....

};
Eg: assign an anonymous function to a variable and call it through a variable

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Closurefunc=function (Closurefunc = function (str) {

Echo $str;

};

$closureFunc ("Hello world!");
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Output: Hello world!

Two: Closures

2.1 Put the anonymous function in the normal function, you can also return the anonymous function, which constitutes a simple closure

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function ClosureFunc1 () {
Func=function () echo "Hello";; Func = function () {echo "Hello";}; Func ();
}
ClosureFunc1 ();
Output: Hello
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2.2 Referencing local variables in anonymous functions

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function ClosureFunc2 () {
Num=1; num = 1; Func = function () {
echo num;
};num; }; Func ();
}
CLOSUREFUNC2 ();
notice:undefined Variable:num
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The above function, after running, will report notice error, that we can not use the local variables in the anonymous function, this time we will refer to a PHP keyword using the code as follows

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function ClosureFunc2 () {
Num=1; num = 1; Func = function () use (num) echo$num;; num) {echo $num;}; Func ();
}
CLOSUREFUNC2 ();
Output: 1
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2.3 Returning anonymous functions

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function closureFunc3 () {
Num=1; num = 1; Func = function () use (num) echo$num;; Return num) {echo $num;}; return func;
}
FUNC=CLOSUREFUNC3 ();//function returns an anonymous function func = closureFunc3 (); function returns an anonymous function func (); And then we're using $func () to call
Output: 1
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2.4 How do we give anonymous functions a reference when we return an anonymous function? In fact, the same as the normal function pass parameters

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function ClosureFunc4 () {
Num=1; num = 1; func = function (str) use (str) use (num) {
echo Num;echo "\ n"; Echo num; echo "\ n"; Echo str;
};
return func;
}func; } func = ClosureFunc4 ();
$func ("Hello, Closure4");
Output:
1
Hello, Closure4.
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2.5 How to use closures to change the value of the variables referenced by the context.

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function ClosureFunc5 () {
Num=1; num = 1; Func = function () use (num) echo "\ n";