How to check for a substring in a string in PHP

A guide on how to use the `strpos` function in PHP to check if a substring exists within a larger string. This is a simple and efficient way to handle string operations in PHP.

In this article, we will explore how to check if a substring exists within a larger string using the strpos function in PHP. This function returns the position of the substring if found, or false if the substring is not present.

PHP Code

<?php
// Main string
$haystack = "This is a simple example string.";

// Substring to check
$needle = "example";

// Check if the substring exists
if (strpos($haystack, $needle) !== false) {
    echo "The substring '$needle' exists in the string.";
} else {
    echo "The substring '$needle' does not exist in the string.";
}
?>

Detailed explanation:

1. $haystack = "...": Variable containing the main string we are checking.
2. $needle = "...": Variable containing the substring we want to find.
3. strpos($haystack, $needle): This function searches for the first occurrence of the substring within the main string.
4. !== false: We use strict comparison to differentiate between false (not found) and position 0 (found at the beginning of the string).
5. echo: Prints the result to the screen.

System requirements:

• PHP version 5 or higher

Tips:

• Be cautious when checking for substrings that could appear at position 0—strict comparison ensures you get accurate results.
• For more complex substring checks, you can use regular expressions with preg_match.

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