PHP Manual: substr

Description

function substr_count(
    string $haystack,
    string $needle,
    int $offset = 0,
    ?int $length = null
): int

substr_count() returns the number of times the needle substring occurs in the haystack string. Please note that needle is case sensitive.

Note:
This function doesn't count overlapped substrings. See the example below!

Parameters

haystack: The string to search in
needle: The substring to search for
offset: The offset where to start counting. If the offset is negative, counting starts from the end of the string.
length: The maximum length after the specified offset to search for the substring. A ValueError is thrown if the offset plus the length is greater than the haystack length. A negative length counts from the end of haystack.

Return Values

This function returns an int.

Errors/Exceptions

Throws a ValueError if needle is empty, if offset is outside of haystack, or if length is outside of the part of haystack that follows offset.

Changelog

Version	Description
8.0.0	Now throws a ValueError instead of raising an `E_WARNING` and returning `false` when `needle` is empty or `offset` or `length` is out of range.
8.0.0	`length` is nullable now.
7.1.0	Support for negative `offset`s and `length`s has been added. `length` may also be `0` now.

Examples

Example #1 A substr_count() example

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

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

// the string is reduced to 's is a test', so it prints 1
echo substr_count($text, 'is', 3), PHP_EOL;

// the text is reduced to 's i', so it prints 0
echo substr_count($text, 'is', 3, 3), PHP_EOL;

// prints only 1, because it doesn't count overlapped substrings
$text2 = 'gcdgcdgcd';
echo substr_count($text2, 'gcdgcd'), PHP_EOL;

// throws an exception because 5+10 > 14
echo substr_count($text, 'is', 5, 10), PHP_EOL;
?>

substr_count