Learn how to use "in_array" function of PHP

Introduction

In this PHP tutorial, I'm Publishing some information about "in_array function" of PHP, which includes syntax, examples, usage, parameter details, return values and some description associated with it. This function is a member of "PHP Array Functions" category in PHP functions library. Below is the list of contents with anchor links pointing to different sections of this article.

List of Contents

  1. Usage and Description,
  2. Syntax,
  3. Parameters,
  4. Return Values,
  5. Practical Examples.

PHP in_array function
PHP in_array function

Usage and Description

This function allows us to check for a searched value (needle) in an array (haystack). Needle can also be an array, Which can be concluded from data type of this parameter in syntax shown below.

Syntax of in_array PHP Function

Here, Below is the syntax of this PHP function.

bool in_array ( mixed $needle 
		, array $haystack [, bool $strict = FALSE] 
		);

Parameters of in_array PHP Function

  • "$needle" - the value of which we are searching in an array i.e. Searched Value.
  • "$haystack" - the array in which we are searching for needle (searched value).
  • "$strict" - defaults to FALSE and if Set to TRUE then this function will also check the data type of both searched value and Matching value found in array.

Return Values

Function output the result in the form of Boolean i.e. either as

  1. TRUE - If Searched Value found in haystack (array) and,
  2. FALSE - If searched value does not exist in haystack (array).

Examples of in_array PHP Function

Below, I'm Publishing some examples which are showing

  • The usage of "in_array PHP function",
  • What happens when we set "$strict" parameter to TRUE and,
  • What if "$needle" parameter i.e. searched value is in the form of array.

Example 1 - Normal Usage

<?php

$myARRAY = array("Alien", "Bravo", "Magic", "Sucks");

if (in_array("Magic", $myARRAY)) {
    echo '"Magic" Word Found in $myARRAY<br/>';
}

if (in_array("Alien", $myARRAY)) {
    echo "System Detected an Alien from Another Galaxy";
}
//-------------------------------------------------------
//This code will output
/*
"Magic" Word Found in $myARRAY,
System Detected an Alien from Another Galaxy 
*/
?> 

Example 2 - $strict parameter set to TRUE

<?php
$myAnotherARR = array('1.10', 12.4, 1.13);

if (in_array('12.4', $myAnotherARR, true)) {

    	echo "'12.4' found with strict check\n<br/>";

}else{
	echo "'12.4' DOES NOT found with strict check\n";
}
/***************************************************/
if (in_array(1.13, $myAnotherARR, true)) {

	echo "1.13 found with strict check\n<br/>";

}else{
	echo "'1.13' DOES NOT found with strict check\n";
}
//-----------------------------------------------------------
//ABOVE CODE WILL OUTPUT
/*
'12.4' DOES NOT found with strict check,
1.13 found with strict check 
*/
?> 

Example 3 - When $needle is also an array

<?php
$mARRAY = array(array('I', 'am'), array('not', 'a'), 'teenager');

if (in_array(array('I', 'am'), $mARRAY)) {
    echo "'I am' was found in $mARRAY\n<br/>";
}

if (in_array(array('A', 'Adult'), $mARRAY)) {
    echo "'A Adult' was found in $mARRAY\n";
}

if (in_array('teenager', $mARRAY)) {
    echo "'teenager' was found\n";
}
//------------------------------------------------
//This code will output
/*
'I am' was found in Array,
 'teenager' was found 
*/
?> 

Still Have Queries

If you still have queries regarding this function or about any section of this article, then, you are free to ask it in comments section below.

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Comments 3 comments

asif 4 years ago

$searchArray = array ('waste', 'waste and recycling', 'waste & recycling');

if (in_array(waste & recycling, $searchArray)) {

echo "i am here";

}

thi not working for me , may be it is becouse '&' charcater, what is the solution for this , thanks


azurelink 4 years ago

How can I get the code to display a line of code only if the value is not found in the array?

Thanks


itech profile image

itech 4 years ago from New Delhi, India Author

@azurelink, you can do that in this way

if(!in_array("waste & recycling", $searchArray)){

echo "key not found in array.";

}

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