PHP: how to get variable from function in another function? [duplicate]

问题

This question already has answers here:

Accessing a variable defined in a parent function (5 answers)

Closed 6 years ago.

Example

function a(){
    $num = 1;

    function b(){
        echo $num; // how to get $num value?
    }
}

In this case global not working, because $num isn't global variable.

回答1:

function a() {
    $num = 1;
    function b($num) {
        echo $num;
    };
    b($num);
}
a();

回答2:

You could use the S_SESSION to get the variable?

function a(){
    $_SESSION['num'] = 1;

    function b(){
        echo $_SESSION['num'];
    }
}

Not sure nested function is the way to go btw.

来源：https://stackoverflow.com/questions/17860930/php-how-to-get-variable-from-function-in-another-function