What is the fastest is_null($y) or $y == null?

Question

What’s the fastest is_null($y) or $y == null?

Answer 1

Phrase Security

The question that really must be asked is this:, "Which is safer to use?". For example, the following expressions:

"oi" == null    => false
""   == null    => true
0    == null    => true
null == null    => true

is_null("oi")   => false
is_null("")     => false
is_null(0)      => false
is_null(null)   => true

"oi" === null   => false
""   === null   => false
0    === null   => false
null === null   => true

Optimizing

The difference between === and is_null is practically irrelevant, unless you have about two million such expressions in a script to require significant optimization.

One of the comments in the PHP documentation says the following (in free translation):

Micro optimization is not worth it.

You had to make it ten million times to notice a difference, a little more than 2 seconds

$a===NULL; Lasted: 1,2424390316s

is_null($a); Lasted: 3,70693397522s

Difference = 2,46449494362s

Differs/10,000,000 = 0,0000002464494362ns

The running time between === NULL and is_null is less than 250 nanoseconds. Go optimize for something worthwhile.

_{Note: I did some tests and the various results did not exceed 100 nanoseconds, and the average difference is between 20 ~ 50 nanoseconds.}

Completion

If you really want to optimize and have security in your code, give preference to the comparison with the triple operator:

$y === null

But there’s no point going through the code looking to optimize these expressions (unless you’re looking for the simple operator ==). Because the difference is so insignificant, that time would be better spent if you were cleaning/improving the code or studying.

More details about logical expressions: /a/69576/8493

More details about logical operators: http://php.net/manual/en/language.operators.comparison.php

Answer 2

It all depends on what you want to check, not just the performance. For example:

<?php

$str1 = "";
$str2 = null;
$str3 = 0;

var_dump(is_null($str1)); // retorna false
var_dump(is_null($str2)); // retorna true
var_dump(is_null($str3)); // retorna false

var_dump($str1 == null); // retorna true
var_dump($str2 == null); // retorna true
var_dump($str3 == null); // retorna true

?>

Answer 3

Your question is tricky because the result is never the same for:

is_null($y) ou $y == null

to compare you should do so on:

is_null($y) ou $y === null

Here yes the results will be similar. It is important to mention that there are situations where the applicability of the operator === is impossible. In cases where it is necessary to use in callbacks only the is_null can be used.

In a direct answer to the question on performance: The difference is not relevant.

But: Both are differentiated approaches to the same problem.

Because...

1. is_null is a function that in the case of PHP runs a C. As a result some latency is obtained.
2. In the case of PHP the difference is minimal because it is a scripting language based on C the interpretation of the code $y === null will still always originate method calls C in either case.

Opinion: I apply according to the situation, but would always choose $y === null because it is a base operator and for this nuclear reason... so the PHP tends to solve with less effort certainly.

Answer 4

There’s no difference between is_null and === null. The unifies difference and that is_null is a function and consequently,

1° The call of the function slows it down, but this speaks of a relatively insignificant time.

2° Because it is a function you can use it from callback, example:

  array_map('is_null', $array);

In the php documentation there is a benchmarking test with 10 million iterations that ends up concluding as follows, the comparison of a variable with an operator is much faster, so don’t use is_null unless you need a callback.

Php - Manual

Answer 5

$y == null.

In terms of performance it is not so relevant the difference, but if used frequently, really worth it just use it.