Check If A String Contains A Specific Word In PHP

Table of Contents

1. Find Exact Match Using the PHP preg_match() Function

1.1 Case Insensitive Search with preg_match()

3. Why to Use preg_match() And Not strpos()

Often, developers want to check string contains a specific word or not in PHP. For that, we can use strpos() and preg_match() functions to do that. Let’s see how to do it.

Check If a String Contains a Specific Word

01 Find Exact Match Using the PHP preg_match() Function

You can use the PHP preg_match() function to check whether a text contains a specific word or not.

Use: The preg_match() function is used to find the exact match of a pattern in a string of text using a regular expression search.

Return: This function will return true if the pattern is matched otherwise it will return false.

Example:

The following example will check for the exact match of the word like we are searching for aware then it will only search for the aware word and not a partial word like "beware", "unaware", "awareness", etc.

<?php 

/* The \b in the pattern indicates a word boundary, so only the distinct */

$string = "Oh! I am also not aware of this ";

if (preg_match("/\aware\b/", $string)) :
    echo "A match was found.";
else:
    echo "A match was not found.";
endif;

The \b expression in the pattern specify a word boundary.

Case Insensitive Search with preg_match()

For case-insensitive search put the "i" after the pattern delimiter as shown below:

<?php

$string = "Oh! I am also not AWARE of this ";

// The "i" after the pattern delimiter indicates a case-insensitive search

if (preg_match("/aware/i", $string)) :
    echo "A match was found.";
else:
    echo "A match was not found.";
endif;

In the above example, we are checking for aware specific word but our string contains a capital AWARE but although it will return A match was found. due to case-insensitive searches.

02 Use the PHP strpos() Function

You can also use the PHP’s strpos() function to check whether a string contains a specific word or not.

The strpos() function will return the position of the first occurrence of a substring in a string. It will return false if the match not found.

Please note that strpos() start searching from 0 index so use strict comparision operator using === or !== otherwise it will considered 0 = false.

Let’s see the example for better understanding:

<?php

$string = "I am not aware of this";

if ( strpos( $string, 'aware' ) !== false ) :
	echo 'true';
else:
	echo 'false';
endif;

You can also check if the string contains a word or not by using other PHP functions like stripos(), strstr(), stristr(), substr_count(), mb_strpos(), etc.

Why to Use preg_match() And Not strpos()

The preg_match() is better for word matching in comparison to strpos() because if you are checking the string contains a word like "are" and if your string contains words like careful, beware, prepare, etc. then strpos() will also return true.

To understand this situation please considered the below example:

<?php

$string = "I am not aware of this";

if ( strpos( $string, 'are' ) !== false ) :
	echo 'true';
else:
	echo 'false';
endif;

The above example should return the false, but it’s returning true as output.

Output:

true

That’s it for now. We hope this article helped you to check if a string contains a specific word in PHP.

Additionally, read our guide:

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