Loop through array keys php

Warning: the benchmark below is not accurate that makes its results wrong.

From my quick and dirty benchmark I did the following 50 times:

Solution 1 [worst]:

foreach [array_keys[$array] as $array_key] {
  echo $array_key;
}

Size of array: 1000000

Min: 0.11363291740417
Avg: 0.11681462287903
Max: 0.14569497108459

Size of array: 9999999

Min: 1.3098199367523
Avg: 1.3250577354431
Max: 1.3673560619354

Solution 2 [middle]:

foreach [$array as $array_key => $array_value] {
  echo $array_key;
}

Size of array: 1000000

Min: 0.10167503356934
Avg: 0.10356130123138
Max: 0.11027193069458

Size of array: 9999999

Min: 1.2077870368958
Avg: 1.2256314325333
Max: 1.2829539775848

Solution 3 [best]:

$array_keys = array_keys[$array];
foreach [$array_keys as $array_key] {
  echo $array_key;
}

Size of array: 1000000

Min: 0.090911865234375
Avg: 0.092938437461853
Max: 0.097810983657837

Size of array: 9999999

Min: 1.0793349742889
Avg: 1.0941110134125
Max: 1.1402878761292

So you can see solution 3 is the quickest option if you only want to look through array keys :]

Hope this helps.

Code:



Note: 
 foreach does not support the ability to suppress error messages using @. 
 Some
more examples to demonstrate usage: 



Unpacking nested arrays with list[]
[PHP 5 >= 5.5.0, PHP 7, PHP 8]
 It is possible to iterate over an array of arrays and unpack the nested array into loop variables by providing a list[] as the value. 
 For example: 



The above example
will output:

  
 You can provide fewer elements in the list[] than there are in the nested array, in which case the leftover array values will be ignored: 



The above example will output:
 A notice will be generated if there aren't enough array elements to fill the
list[]: 



The above example will output:
Notice: Undefined offset: 2 in example.php on line 7
A: 1; B: 2; C: 

Notice: Undefined offset: 2 in example.php on line 7
A: 3; B: 4; C: 
 Sanusi Hassan ¶

  
8
days ago

destructure array elements
you can unpac nested array elements using the following

 Okafor Chiagozie ¶
5 days ago

An easier way to unpack nested array elements
$array = [
    [1, 2],
    [3, 4],
];
foreach [$array as [$a, $b]] {
    echo "A: $a; B: $b\n";
}

 
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