String Functions
PHP Manual

substr_compare

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

Description

int substr_compare ( string $main_str , string $str , int $offset [, int $length [, bool $case_insensitivity = false ]] )

substr_compare compares main_str from position offset with str up to length characters.

Parameters

main_str

The main string being compared.

str

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 str compared to the length of main_str less the offset.

case_insensitivity

If case_insensitivity is TRUE, comparison is case insensitive.

Return Values

Returns < 0 if main_str from position offset is less than str, > 0 if it is greater than str, and 0 if they are equal. If offset is equal to or greater than the length of main_str, or the length is set and is less than 1 (prior to PHP 5.5.11), substr_compare prints a warning and returns FALSE.

Changelog

Version Description
5.5.11 length may now be 0.
5.1.0 Added the possibility to use a negative offset.

Examples

Example #1 A substr_compare example

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

See Also

  • strncmp