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substr_compare

PHP function Edit on GitHub ✎

(PHP 5, PHP 7, PHP 8)

Binary safe comparison of two strings from an offset, up to length characters

Description

substr_compare(string $haystack, string $needle, int $offset, int|null $length = null, bool $case_insensitive = false): int

substr_compare() compares haystack from position offset with needle up to length characters.

Parameters

haystack: The main string being compared.
needle: The secondary string being compared.
offset: The start position for the comparison. If negative, it starts counting from the end of the string.
length: The length of the comparison. The default value is the largest of the length of the needle compared to the length of haystack minus the offset.
case_insensitive: If case_insensitive is true, comparison is case insensitive.

Return Values Return

If offset is equal to (prior to PHP 7.2.18, 7.3.5) or greater than the length of haystack, or the length is set and is less than 0, substr_compare() prints a warning and returns false.

Changelog

Version	Description
8.0.0	`length` is nullable now.
7.2.18, 7.3.5	`offset` may now be equal to the length of `haystack`.

Examples

A substr_compare() example

php

<?php
echo substr_compare("abcde", "bc", 1, 2), PHP_EOL; // 0
echo substr_compare("abcde", "de", -2, 2), PHP_EOL; // 0
echo substr_compare("abcde", "bcg", 1, 2), PHP_EOL; // 0
echo substr_compare("abcde", "BC", 1, 2, true), PHP_EOL; // 0
echo substr_compare("abcde", "bc", 1, 3), PHP_EOL; // 1
echo substr_compare("abcde", "cd", 1, 2), PHP_EOL; // -1
echo substr_compare("abcde", "abc", 5, 1), PHP_EOL; // -1
?>