PHP array vs [ ] in method and variable declaration

Question

I have a question about PHP syntax.

When defining functions and variables, which convention should I use?

I know they do the same thing in practice but I would like to know which method conforms to best practice standards.

Variables

public $varname = array();

or

public $varname = [];

Methods

public function foo($bar = array()){}

or

public function foo($bar = []){}

Expect the code to be ran on php version < 5.4? use array() otherwise pick one and be consistent. There is no official standard. — Steve
– Steve, Commented Oct 30, 2014 at 11:40
That said, if you are using a framework (and you probably should be), then follow whatever practice the framework uses — Steve
– Steve, Commented Oct 30, 2014 at 11:42
Thanks, I am using cakphp 3.0 with some zend mixed in. CakePHP seems to be mixing it up a bit and have not investigated zend. Will never deploy on anything beneath 5.4. Think [] helps with legibility since it gives a distinction between method and array braces. — Dieter Gribnitz
– Dieter Gribnitz, Commented Oct 30, 2014 at 11:48
I prefer square brackets as well, as its consistent with many other languages. As i said, as long as you are consistent yourself you will be fine — Steve
– Steve, Commented Oct 30, 2014 at 11:53

Movahhedi · Accepted Answer · 2022-06-08 08:46:03Z

97

PSR-2 and PSR-12 (by PHP Framework Interoperability Group) do not mention short array syntax. But as you can see in chapter 4.3 they use short array syntax to set the default value of $arg3 to be an empty array.

So for PHP >= 5.4 the short array syntax seems to be the de-facto standard. Only use array(), if you want your script to run on PHP <5.4.

edited Jun 8, 2022 at 8:46

Movahhedi

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answered Oct 30, 2014 at 11:52

BreyndotEchse

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Comments

Community · Accepted Answer · 2020-06-20 09:12:55Z

34

from PHP docs:

As of PHP 5.4 you can also use the short array syntax, which replaces array() with [].

<?php
$array = array(
    "foo" => "bar",
    "bar" => "foo",
);

// as of PHP 5.4
$array = [
    "foo" => "bar",
    "bar" => "foo",
];
?>

if you'd try using '[]' notation in earlier version than 5.4, it will fail, and PHP will throw a syntax error

for backward-compatibility you should use array() syntax.

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Oct 30, 2014 at 11:41

Nitsan Baleli

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3 Comments

Steve Over a year ago

Not downvoted, but i dont see how this answers the question at all

Nitsan Baleli Over a year ago

I think it answers the question, trying to use '[]' notation in a version prior to 5.4 is out of the question and is impossible.

SOFe Over a year ago

The question asks "which convention should I use", and the answer is "you should use array() to preserve backward compatibility". How is it irrelevant?

Aurangzeb · Accepted Answer · 2019-06-23 14:12:33Z

10

just made a test to see how [] performs vs array() here is what I got

testing 1 million []s ( with $arr[] = [] )
started at : 1561298821.8754
ended at: 1561298822.6881
difference: 0.81266021728516 seconds 

testing 1 million array()s ( with array_push( $arr, array()) )
started at : 1561298822.6881
ended at: 1561298823.843
difference: 1.1549289226532 seconds 

testing 1 million []s ( again while the processor is hotter)
started at : 1561298823.8431
ended at: 1561298824.7448
difference: 0.9017219543457 seconds

so [] performed about 20% faster

answered Jun 23, 2019 at 14:12

Aurangzeb

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6 Comments

My1 Over a year ago

but you are performing a different operation (set to empty array vs array_push), so it's not apples to apples

Aurangzeb Over a year ago

$arr[] = [] and array_push( $arr, array()) performs the same operation, appends an empty array to an array (doesn't set array to an empty array) , the people who upvoted your post are most likely newbies

My1 Over a year ago

oh, now that you explain what it does, it actually makes sense, except it seems pointless appending an empty array as the next element

s3c Over a year ago

Upvoted OP's comment, due to fallacy of the first comment. Still I would argue it's the same apples being compared. Perhaps a better approach would be to compare $arr[] = [] and $arr[] = array(). And if you wish also (separately) $arr[] = [] and array_push( $arr, [] ).

Alex Over a year ago

Actually tested it and have dug into it. And indeed [] is a lot faster. And that's because [] is now what PHP deems as the primary operator. array() gets translated to [] first and then executed.

|

Valentin Rodygin · Accepted Answer · 2014-10-30 11:41:24Z

7

That depends on what version of PHP you are targeting. For the best backward compatibility, I'd recommend you to use array(). If you don't care about older versions (< PHP 5.4), I'd recommend you to use a shorter version.

answered Oct 30, 2014 at 11:41

Valentin Rodygin

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Comments

Andrei Nikolaenko · Accepted Answer · 2022-11-07 07:56:44Z

1

it's obvious that new PHP projects should use [] because it's shorter, cleaner and similar to other languages like JS.

answered Nov 7, 2022 at 7:56

Andrei Nikolaenko

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