String Functions
PHP Manual


(PHP 5, PHP 7)

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


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.



The main string being compared.


The secondary string being compared.


The start position for the comparison. If negative, it starts counting from the end of the string.


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.


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 5.6), substr_compare() prints a warning and returns FALSE.


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


Example #1 A substr_compare() example

echo substr_compare("abcde""bc"12); // 0
echo substr_compare("abcde""de", -22); // 0
echo substr_compare("abcde""bcg"12); // 0
echo substr_compare("abcde""BC"12true); // 0
echo substr_compare("abcde""bc"13); // 1
echo substr_compare("abcde""cd"12); // -1
echo substr_compare("abcde""abc"51); // warning

See Also

String Functions
PHP Manual