How to check if a String contains a Specific Character in PHP ?

In PHP, determining whether a string contains a specific character is a common task. Whether you're validating user input, parsing data, or performing text processing, PHP provides several methods to check for the presence of a particular character within a string efficiently.

Here are some common approaches:

Using strpos( ) function

The strpos() function in PHP finds the position of a specific character or substring within a string. If the character or substring is found, it returns the position; otherwise, it returns `false`. This helps check for presence.

Example: Implementation to check if a string contains a specific character using the strpos( ) function

<?php
$string = "Hello, world!";
$char = "o";

// Using strpos() function
if (strpos($string, $char) !== false) {
    echo "The string contains the character '$char'.";
} else {
    echo "The string does not contain the character '$char'.";
}

?>

The string contains the character 'o'.

Using strstr( ) function

The strstr() function in PHP checks if a specific substring exists within a string. It returns the portion of the string from the first occurrence of the substring to the end. If the substring is not found, it returns `false`, enabling substring validation.

Example: Implementation to check if a string contains a specific character using strstr( ) function.

<?php
$string = "Hello, world!";
$char = "o";

// Using strstr() function
if (strstr($string, $char) !== false) {
    echo "The string contains the character '$char'.";
} else {
    echo "The string does not contain the character '$char'.";
}
?>

The string contains the character 'o'.

Using preg_match() function

The preg_match() function is used to perform a regular expression match. It allows for more complex pattern matching, including checking for the presence of specific characters using regular expressions.

Example: In this example we checks if a specific character exists in a given string using the preg_match() function. It outputs a message indicating whether the character is present or not.

<?php
// Nikunj Sonigara
$string = "Hello, world!";
$char = "o";
 
// Using preg_match() function
if (preg_match('/' . preg_quote($char, '/') . '/', $string)) {
    echo "The string contains the character '$char'.";
} else {
    echo "The string does not contain the character '$char'.";
}
?>

The string contains the character 'o'.