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PHP PHP Functions Introducing Functions PHP Function Arguments

見綸 陳
見綸 陳
6,333 Points
Posted by 見綸 陳
見綸 陳
6,333 Points

Why don't global $variable

In previous course video, we write global $current_user in the function to make the function reach outside variable($current_user)

Again, in this video we have a global variable outside the function. WHY DON'T WE CALL THE GOBAL VARIABLE ?

I also do some test to reach the global variable from the function. But the outcome still same. Is there any reason that we don't have to write: global $variable in this case?

        <?php
        function welcome_dialog($user_array) {
            if(is_array($user_array)) {
                global $name;  // ------- I ADD THIS LINE TO TEST -------
                foreach($user_array as $name) {
                    echo "Hello, $name, how are you?</br>"; 
                }
            } else {
                echo 'Hello friends</br>';
            }
        }

        $name = array(
            'Kcin',
            'Sharon',
            'Brother',
            'Sister'
        );

        welcome_dialog($name);

        ?>

1 Answer

Codin - Codesmite
Codin - Codesmite
8,600 Points
Codin - Codesmite
Codin - Codesmite
8,600 Points

It isn't required because the values of $name array are passed into the functions arguments.

<?php
    function welcome_dialog($user_array) {
        if(is_array($user_array)) { 
            foreach($user_array as $name) { 
                echo "Hello, $name, how are you?</br>"; 
            }
        } else {
            echo 'Hello friends</br>';
        }
    }

    $name = array(
        'Kcin',
        'Sharon',
        'Brother',
        'Sister'
    );

    welcome_dialog($name); // Here you are declaring $name array as arguement for the function.

    ?>

In the function where you have foreach($user_array as $name) { It is not calling the global array $name for the values, it is looping the values of $user_array declared in the functions arguments, these are the same values from global $name array as they are declared in the use of the function at the end of the code: welcome_dialog($name);

I've changed the code a bit to make it a bit clearer as to what is happening:

<?php
    function welcome_dialog($user_array) {
        if(is_array($user_array)) {
            foreach($user_array as $canBeAnything) { 
                echo "Hello, $canBeAnything, how are you?</br>"; 
            }
        } else {
            echo 'Hello friends</br>';
        }
    }

    $globalArrayName = array(
        'Kcin',
        'Sharon',
        'Brother',
        'Sister'
    );

    welcome_dialog($globalArrayName);

    ?>

Here are some more simplified examples:

<?php
// This requires global

    $x = 75;
    $y = 25;

    function addition() {
        global $x;
        global $y;
        $z = $x + $y;
    }

    addition();
    echo $z;
?> 

<?php
// This does not requires global as the values of $x and $y are called as arguements for the addition function

    $x = 75;
    $y = 25;

    function addition($x,$y) {
        $z = $x + $y;
    }

    addition($x,$y);
    echo $z;
?>

Hope this helped explain :)

見綸 陳
見綸 陳
6,333 Points
見綸 陳
見綸 陳
6,333 Points

Pretty clear, thanks a lot!

Andrew Dovganyuk
Andrew Dovganyuk
10,633 Points
Andrew Dovganyuk
Andrew Dovganyuk
10,633 Points

the echo $z; must be inside the function to display z