php变量范围问题

Question

Here's the code first:

<?php

$test = 'nothing';

function check_test(){
    global $test;

    echo 'The test is '.$test.'
';

}


function run($lala){
    $test = $lala;
    check_test();
}


check_test();

run('Test 2');
run('Test 3');


check_test();

AFAIK in Python it would work, because it searches variables to upper scope, but looks like it works different in php. So here is the question: how can I achieve that behaviour - so function will use first variable occurance and won't start looking from the higher scope-level. In this example I wanted to get output.

The test is nothing
The test is Test 2
The test is Test 3
The test is nothing

But got only

The test is nothing

for 4 times.

Means that very first variable declaration was used. Much appreciate with any suggestions to this!

This is not duplicate, I understand the conception of scope, I'am asking about is it possible to achieve certain behaviour in this snippet.

UPD: I can't use proposed methods because we use pthreads and each function will run in the same time and global variable will be changed every second and that's not what I want. Instead I need that every thread will be using its own "local" global test variable.

Answer 1

You need to use global here also.

function run($lala){
    global $test = $lala;
    check_test();
}

but there is a problem when the last check_test(); function call then you will get he same value of $test as for 3rd one.

Example:

The test is nothing
The test is Test 2
The test is Test 3
The test is Test 3

Suggestion:

So if you really want to get the output like you show the you need to pass a parameter to your check_test() function.

Example:

function check_test($arg= null) {
    global $test;

    $arg= ($arg== null) ? $arg: $test;

    echo "The test is ".$arg."<br/>";
}

function run($par){
    check_test($par);
}

The test is nothing
The test is Test 2
The test is Test 3
The test is nothing