PHP in_array() Function (original) (raw)

Summary: in this tutorial, you will learn how to use the PHP in_array() function to check if a value exists in an array.

Introduction to the PHP in_array() function #

The in_array() function returns true if a value exists in an array.

Here’s the syntax of the in_array() function:

in_array ( mixed <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>n</mi><mi>e</mi><mi>e</mi><mi>d</mi><mi>l</mi><mi>e</mi><mo separator="true">,</mo><mi>a</mi><mi>r</mi><mi>r</mi><mi>a</mi><mi>y</mi></mrow><annotation encoding="application/x-tex">needle , array </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">n</span><span class="mord mathnormal">ee</span><span class="mord mathnormal">d</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">e</span><span class="mpunct">,</span><span class="mspace" style="margin-right:0.1667em;"></span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.02778em;">rr</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.03588em;">y</span></span></span></span>haystack , bool $strict = false ) : boolCode language: PHP (php)

In this syntax:

The in_array() function searches for the $needle in the $haystack using the loose comparison (==). To use the strict comparison (===), you need to set the $strict argument to true.

If the value to check is a string, the in_array() function will search for it case-sensitively.

The in_array() function returns true if the $needle exists in the $array; otherwise, it returns false.

PHP in_array() function examples #

Let’s take some examples of using the in_array() function.

1) Simple PHP in_array() function examples #

The following example uses the in_array() function to check if the value 'update' is in the $actions array:

`<?php

$actions = [ 'new', 'edit', 'update', 'view', 'delete', ]; result=inarray(′update′,result = in_array('update', result=ina​rray(′update′,actions);

var_dump($result); // bool(true)`Code language: PHP (php)

Try it

Output:

bool(true)Code language: PHP (php)

It returns true.

The following example returns false because the publish value doesn’t exist in the $actions array:

`<?php

$actions = [ 'new', 'edit', 'update', 'view', 'delete', ]; result=inarray(′publish′,result = in_array('publish', result=ina​rray(′publish′,actions);

var_dump($result); // bool(false)`Code language: PHP (php)

Try it

The following example returns false because the value 'New' doesn’t exist in the $actions array. Note that the in_array() compares the strings case-sensitively:

`<?php

$actions = [ 'new', 'edit', 'update', 'view', 'delete', ]; result=inarray(′New′,result = in_array('New', result=ina​rray(′New′,actions);

var_dump($result); // bool(false)`Code language: PHP (php)

Try it

Output:

bool(false)Code language: PHP (php)

2) Using PHP in_array() function with the strict comparison example #

The following example uses the in_array() function to find the number 15 in the $user_ids array. It returns true because the in_array() function compares the values using the loose comparison (==):

`<?php

$user_ids = [10, '15', '20', 30]; result=inarray(15,result = in_array(15, result=ina​rray(15,user_ids);

var_dump($result); // bool(true)`Code language: PHP (php)

Try it

To use the strict comparison, you pass true to the third argument ($strict) of the in_array() function as follows:

`<?php

$user_ids = [10, '15', '20', 30]; result=inarray(15,result = in_array(15, result=ina​rray(15,user_ids, true);

var_dump($result); // bool(false)`Code language: PHP (php)

This time the in_array() function returns false instead.

Using the PHP in_array() function with the searched value is an array example #

The following example uses the in_array() function with the searched value is an array:

`<?php

$colors = [ ['red', 'green', 'blue'], ['cyan', 'magenta', 'yellow', 'black'], ['hue', 'saturation', 'lightness'] ];

if (in_array(['red', 'green', 'blue'], $colors)) { echo 'RGB colors found'; } else { echo 'RGB colors are not found'; }`Code language: PHP (php)

Try it

Output:

RGB colors foundCode language: PHP (php)

4) Using PHP in_array() function with an array of objects example #

The following defines the Role class that has two properties $id and $name:

`<?php

class Role { private $id;

private $name;

public function __construct($id, $name)
{
 <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>t</mi><mi>h</mi><mi>i</mi><mi>s</mi><mo>−</mo><mo>&gt;</mo><mi>i</mi><mi>d</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">this-&gt;id = </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">t</span><span class="mord mathnormal">hi</span><span class="mord mathnormal">s</span><span class="mord">−</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">i</span><span class="mord mathnormal">d</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>id;
 <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>t</mi><mi>h</mi><mi>i</mi><mi>s</mi><mo>−</mo><mo>&gt;</mo><mi>n</mi><mi>a</mi><mi>m</mi><mi>e</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">this-&gt;name = </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">t</span><span class="mord mathnormal">hi</span><span class="mord mathnormal">s</span><span class="mord">−</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.4306em;"></span><span class="mord mathnormal">nam</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>name;
}

}`Code language: PHP (php)

This example illustrates how to use the in_array() function to check if a Role object exists in an array of Role objects:

`<?php

class Role { private $id;

private $name;

public function __construct($id, $name)
{
 <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>t</mi><mi>h</mi><mi>i</mi><mi>s</mi><mo>−</mo><mo>&gt;</mo><mi>i</mi><mi>d</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">this-&gt;id = </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">t</span><span class="mord mathnormal">hi</span><span class="mord mathnormal">s</span><span class="mord">−</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">i</span><span class="mord mathnormal">d</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>id;
 <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>t</mi><mi>h</mi><mi>i</mi><mi>s</mi><mo>−</mo><mo>&gt;</mo><mi>n</mi><mi>a</mi><mi>m</mi><mi>e</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">this-&gt;name = </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">t</span><span class="mord mathnormal">hi</span><span class="mord mathnormal">s</span><span class="mord">−</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.4306em;"></span><span class="mord mathnormal">nam</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>name;
}

}

$roles = [ new Role(1, 'admin'), new Role(2, 'editor'), new Role(3, 'subscribe'), ];

if (in_array(new Role(1, 'admin'), $roles)) { echo 'found it'; }`Code language: PHP (php)

Try it

Output:

found it!Code language: PHP (php)

If you set the $strict to true, the in_array() function will compare objects using their identities instead of values. For example:

`<?php

class Role { private $id;

private $name;

public function __construct($id, $name)
{
 <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>t</mi><mi>h</mi><mi>i</mi><mi>s</mi><mo>−</mo><mo>&gt;</mo><mi>i</mi><mi>d</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">this-&gt;id = </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">t</span><span class="mord mathnormal">hi</span><span class="mord mathnormal">s</span><span class="mord">−</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.6944em;"></span><span class="mord mathnormal">i</span><span class="mord mathnormal">d</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>id;
 <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>t</mi><mi>h</mi><mi>i</mi><mi>s</mi><mo>−</mo><mo>&gt;</mo><mi>n</mi><mi>a</mi><mi>m</mi><mi>e</mi><mo>=</mo></mrow><annotation encoding="application/x-tex">this-&gt;name = </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.7778em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">t</span><span class="mord mathnormal">hi</span><span class="mord mathnormal">s</span><span class="mord">−</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">&gt;</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:0.4306em;"></span><span class="mord mathnormal">nam</span><span class="mord mathnormal">e</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span></span></span></span>name;
}

}

$roles = [ new Role(1, 'admin'), new Role(2, 'editor'), new Role(3, 'subscribe'), ];

if (in_array(new Role(1, 'admin'), $roles, true)) { echo 'found it!'; } else { echo 'not found!'; }`Code language: PHP (php)

Try it

Output:

not found!Code language: PHP (php)

Summary #

Did you find this tutorial useful?