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substr_count

PHP function Edit on GitHub ✎

(PHP 4, PHP 5, PHP 7, PHP 8)

Count the number of substring occurrences

Description

substr_count(string $haystack, string $needle, int $offset = 0, int|null $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

A substr_count() example

php

<?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;
?>