Binary safe comparison of two strings from an offset, up to length characters
Syntax
substr_compare ( string $main_str , string $str , int $offset [, int $length [, bool $case_insensitivity = FALSE ]] ) : int
Parameters
main_strThe main string being compared.
strThe secondary string being compared.
offsetThe start position for the comparison. If negative, it starts counting from the end of the string.
lengthThe length of the comparison. The default value is the largest of the length of the str compared to the length of main_str minus the offset.
case_insensitivityIf case_insensitivity is TRUE, comparison is case insensitive.
Return
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 (prior to PHP 7.2.18, 7.3.5) or greater than the length of main_str, or the length is set and is less than 0, (or, prior to PHP 5.5.11, less than 1) substr_compare() prints a warning and returns FALSE.
Examples
1 · main_str str offset · Negative
<? $main_str = "ABCDEabcde"; $str = "a"; $offset = -5; $return = substr_compare($main_str, $str, $offset); echo $return; ?>
1
2 · main_str str offset · Non-negative
<? $main_str = "ABCDEabcde"; $str = "a"; $offset = 5; $return = substr_compare($main_str, $str, $offset); echo $return; ?>
1
3 · length
<? $main_str = "ABCDEabcde"; $str = "a"; $offset = 5; $length = 1; $return = substr_compare($main_str, $str, $offset, $length); echo $return; ?>
0
4 · case_insensitivity
<? $main_str = "ABCDEabcde"; $str = "a"; $offset = 0; $length = 1; $case_insensitivity = true; $return = substr_compare($main_str, $str, $offset, $length, $case_insensitivity); echo $return; ?>
0
