(PHP 5, PHP 7)
substr_compare — Binary safe comparison of two strings from an offset, up to length characters
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.
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.
Returns < 0 if haystack from position offset is less than needle, > 0 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.
| 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. |
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
?>
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https://www.php.net/manual/en/function.substr-compare.php