How to access global variables inside a function in PHP

In PHP, global variables are variables accessible in functions, classes, and scripts. These variables can be declared and initialized by specifying the $GLOBALS array, or they can be declared as global variables inside the function. However, it is not easy to access global variables in a function, because the function is a local scope structure, so how to access global variables inside the function?

One way is to use the $GLOBALS array. For example:

<?php $number = 50;

function change_number() {
    global $number;
    $number = 100;
}

change_number();
echo $number; // 输出: 100
?>

In the above example, we have used the global keyword to declare $number as a global variable, so inside the function $number After the value of is modified, it also changes outside the function.

Another approach is to use $GLOBALSsuper global arrays. For example:

<?php $number = 50;

function change_number() {
    $GLOBALS[&#39;number&#39;] = 100;
}

change_number();
echo $number; // 输出: 100
?>

In the above example, the $number key value in $GLOBALS corresponds to the global variable $number. When we modify the value of $GLOBALS['number'] inside the function, the value of the global variable $number is also modified.

It should be noted that excessive use of global variables may make the code difficult to maintain. If you need to use a lot of variables inside a function, it's better to pass them into the function from outside to avoid dependencies between functions.

To sum up, you can access and modify global variables using the global keyword or the $GLOBALS array. However, you need to use global variables with caution and use variables as function parameters whenever possible to avoid code that is cluttered and difficult to maintain.

The above is the detailed content of How to access global variables inside a function in PHP. For more information, please follow other related articles on the PHP Chinese website!