PHP: Add to an Array

A close up of PHP code

It’s very common to find yourself working with Arrays in any language, and PHP is no exception. If you’re reading this, you probably want to find out how to add to an array in PHP but there’s one thing to cover first! Unlike most other languages, arrays in PHP are just an ordered map! Let’s declare an array to work with.

Arrays can be declared similarly to map, but you can freely omit the keys.

$array = array(1,2,3,4);

Now that we have an array, we can see how easy it is to add to an array like so:

$array[] = 5;

Adding to an array in PHP really is as simple as assigning a new value to a blank index!

There’s some interesting information regarding the addition of an element into an array with PHP though. For one: during the scope of the addition, the array is treated like a stack (keep in mind that this is actually an ordered-map, remember?). Additionally, if an array does not yet exist and you use $array[] = 5, a new array will be created.

Theres an alternative solution as well, and that’s by calling the array_push function. If you have to use it, the array_push function’s definition looks like this:

array_push ( array &$array [, mixed $... ] ) : int

Notice that it returns an int. That int represents the new size of the array. Generally, you won’t want to use this pattern and will instead favor the assignment pattern from before. The reason why is that use of array_push will introduce an additional function call and the overhead that comes with that.

It’s worth mentioning that, with this pattern, if you don’t provide an array as the first argument to this function, an error will be raised.

If you’re interested in learning more about PHP, you can find more of my PHP related posts here. Additionally, you can find more information about arrays in the PHP manual.

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