PHP substr_compare() Function
Topic: PHP String ReferencePrev|Next
Description
The substr_compare() function compares two strings from a specified start position, up to a specified length of characters. The comparison is case-sensitive by default.
The following table summarizes the technical details of this function.
| Return Value: |
Returns a negative value ( If start is set to a value greater than the length of main_str, or the length is set to a value less than 0, this function returns
FALSE. |
|---|---|
| Changelog: | Since PHP 7.3.5, the start may now be equal to the length of main_str. |
| Version: | PHP 5+ |
Syntax
The basic syntax of the substr_compare() function is given with:
The following example shows the substr_compare() function in action.
Example
Run this code »<?php
// Sample strings
$main_str = "Blackbird";
$str = "bird";
// Comparing strings
echo substr_compare($main_str, $str, 5);
?>Parameters
The substr_compare() function accepts the following parameters.
| Parameter | Description |
|---|---|
| main_str | Required. Specifies the main string being compared. |
| str | Required. Specifies the secondary string being compared. |
| start | Required. Specifies the start position for the comparison. If it is negative, counting will start from the end of the string. |
| length | Optional. Specifies the 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 start. |
| case_insensitivity | Optional. If set to true, the comparison will be case-insensitive. Default value is false which perform a case-sensitive comparison. |
More Examples
Here're some more examples showing how substr_compare() function actually works:
The following example simply compares the two strings from the beginning.
Example
Run this code »<?php
// The two strings are equal
echo substr_compare("Blackbird", "Blackbird", 0)."<br>";
// The main string is greater than the secondary string
echo substr_compare("Blackbird", "Black", 0)."<br>";
// The main string is less than the secondary string
echo substr_compare("Black", "Blackbird", 0);
?>The following example demonstrates the usage of different parameters.
Example
Run this code »<?php
// Comparing strings
echo substr_compare("Blackbird", "Black", 0)."<br>";
echo substr_compare("Blackbird", "black", 0, 5, true)."<br>";
echo substr_compare("Blackbird", "bird", -4, 4)."<br>";
echo substr_compare("Blackbird", "bird", 2, 4)."<br>";
echo substr_compare("Blackbird", "lack", 1, 5);
?>
