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16

If I define an array in PHP such as (I don't define its size):

$cart = array();

Do I simply add elements to it using?:

$cartData[] = 13;
$cartData[] = "foo";
$cartData[] = obj;

Don't arrays in PHP have a add method, i.e. cart.add(13)?

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4 Answers

up vote 121 down vote accepted

Both array_push and the method you described will work.

<?php
$cart = array();
$cart[] = 13;
$cart[] = 14;
// etc
?>

Is the same as: 

<?php
$cart = array();
array_push($cart, 13);
array_push($cart, 14);

// Or 
$cart = array();
array_push($cart, 13, 14);
?>
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24  
As stated in the PHP documentation, if you're only pushing a single element every time (like in a loop) or a single element once, it's best to use the $cart[] = 13 method not only because it's less characters to do the same operation, but it also doesn't impose the performance overhead of a function call, which array_push() would. Edit: But, great answer. Effectively the same, and majority of uses won't even notice a performance difference, but helps to know those nuances. – Mattygabe Jan 15 '11 at 5:10
up vote 21 down vote

Its better to not use array_push and just use what you suggested. The functions just add overhead.

//dont need to define the array, but in many cases its the best solution.
$cart = array();

//automatic new integer key higher then the highest existing integer 
//key in the array, starts at 0
$cart[] = 13;
$cart[] = 'text';

//numeric key
$cart[4] = $object;

//text key (assoc)
$cart['key'] = 'test';
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3  
"If you're adding multiple values to an array in a loop, it's faster to use array_push than repeated [] = statements" php.net/manual/en/function.array-push.php#84959 – Ollie Glass Dec 18 '10 at 17:15
1  
Absolutely correct if your use-case is adding a single item or items one at a time. If all values are known at the same time, it's probably best just to use the array_push notation depending on how many items must be added the extra characters from re-typing the array name each time may be more of a performance hindrance than the function call over-head. As always, judgment should be exercised when choosing. Good answers! – Mattygabe Jan 15 '11 at 5:13
up vote 1 down vote

It's called array_push: http://il.php.net/function.array-push

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up vote 1 down vote

You can use array_push. It adds the elements to the end of the array, like in a stack.

You could have also done it like this:

$cart = array(13, "foo", $obj);
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