String Functions
PHP Manual

substr_compare

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

Description

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

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

Returns -1 if haystack from position offset is less than needle, 1 if it is greater than needle, and 0 if they are equal. 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
8.2.0 This function now returns -1 or 1, where it previously returned a negative or positive number.
8.0.0 length is nullable now.
7.2.18, 7.3.5 offset may now be equal to the length of haystack.

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