PHP Function Array values not changing

Question

Ive created a function that takes an array as a parameter and changes all values to 4, but it doesn't work and i don't understand why. Really bothering me, could use help thank you!

$cup3 = array (1,4,3,5,7,2);
roll($cup3);
print_r($cup3);

function roll($array)
{
    foreach($array as &$value)
    {
        $value = 4;
    }
    return $array;
}

Output: (1,4,3,5,7,2) instead of all 4s

AbraCadaver · Accepted Answer · 2017-03-03 22:45:54Z

3

Either pass by reference &$array to edit $cup3 directly:

roll($cup3);
print_r($cup3);

function roll(&$array)
{
    foreach($array as &$value)
    {
        $value = 4;
    }
}

Or use the return from the function:

$cup3 = roll($cup3);
print_r($cup3);

function roll($array)
{
    foreach($array as &$value)
    {
        $value = 4;
    }
    return $array;
}

answered Mar 3, 2017 at 22:45

AbraCadaver

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3 Comments

Badal Parekh Over a year ago

Thanks a lot, really appreciate it!

ashnazg Over a year ago

The key insight here is that the array is passed in by value, unlike an object that would be passed in by reference. If you want the array's modifications in the function body to persist beyond the function, you'd have to explicitly pass it in by reference, like in @AbraCadaver 's first example.

Badal Parekh Over a year ago

important lesson that I will remember. gotta remember the basics.

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