PHP substr_count() Function: Usage, Parameters, and Examples

The substr_count() function in PHP returns the number of times a substring ( needle) appears in a larger string ( haystack), with case‑sensitivity.

Signature:

int substr_count(string $haystack, string $needle[, int $offset = 0[, int $length]])

Parameters: haystack: The string to search within. needle: The substring to count. offset (optional): The position in haystack where counting starts. length (optional): The maximum length to search after the offset; if the sum of offset and length exceeds the length of haystack, a warning is issued.

Return value: An integer representing the count of needle occurrences.

Examples:

<?php
$text = 'This is a test';
echo strlen($text); // 14

echo substr_count($text, 'is'); // 2

// Using offset
echo substr_count($text, 'is', 3); // 0 (search starts after "is")

// Using offset and length
echo substr_count($text, 'is', 3, 3); // 0

// Demonstrating warning when offset+length > haystack length
echo substr_count($text, 'is', 5, 10); // warning, result 1 (non‑overlapping)

$text2 = 'gcdgcdgcd';
echo substr_count($text2, 'gcdgcd'); // 1 (does not count overlapping)
?>

The examples illustrate basic counting, the effect of offset and length parameters, and the fact that overlapping substrings are not counted.