Question

If you simply want to assign values to a variable this way:

$array[]="value 1" and $array[]="value 2"

do you first have to declare $array=array()? Obviously you don’t HAVE to, as it works without it, but why would you do that then? Or what is the benefit of doing it?

Answer 1

What you are describing is not a declaration but an initialization. You are not declaring $array is an array, you are assigning it a value (empty array).

Such an initialization can be used to establish a scope, and perhaps it can make the code more readable (although I can’t see how), but usually it is only done when you specifically want an empty array. The classic example is when using the [] syntax to append to an array. Consider the following:

$a = 'old value';
$a = array();
$a[] = 1;
$a[] = 2;
$a[] = 3;

Without the second line, this will produce an error.

By the way, The array() command isn’t an ordinary function. It’s a language construct, and starting with PHP 5.4 you can replace it with the shorter [] syntax:

$a = 'old value';
$a = [];
$a[] = 1;
$a[] = 2;
$a[] = 3;