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PHP: substr_compare() function

Description

The substr_compare() function is used to compare two strings from a given starting position in the main string.

Version:

(PHP 5)

Syntax:

substr_compare(main_string, compare_string, star_pos, length, case_insensitivity)

Parameters:

Name Description Required /
Optional		 Type
main_string The main string. Required String
compare_string The string to be compared. Required String
star_pos The starting position in the main string. Required Integer
length A positive number : Start at the specified position in the string.
A negative number : Start at a specified position from the end of the string.		 Optional Integer
case_insensitivity If set TRUE comparison is case insensitive. Optional Boolean

Return value:

0 : If two main_string=compare_string
<0 : if the length of the main_string from the starting position is less than the compare_string
>0 : if the length of the main_string from the starting position is greater than the compare_string.

Value Type: Integer.

Pictorial Presentation

string_substr_compare

Example: 

<?php
echo substr_compare('uvwxyz', 'uv', 1, 2).'<br>';
echo substr_compare('uvwxyz', 'uvw', 1, 2).'<br>';
echo substr_compare('uvwxyz', 'uv', -2, 2).'<br>';
echo substr_compare('uvwxyz', 'xy', 1, 2).'<br>';
echo substr_compare('uvwxyz', 'xyz', -3, 3).'<br>';
?>

Output: 

1
1
4
-2
0

View the example in the browser

See also

PHP Function Reference

Previous: strtr
Next: substr_count



PHP: Tips of the Day

In PHP, there are two versions of logical AND and OR operators.

Operator True if
$a and $b Both $a and $b are true
$a && $b Both $a and $b are true
$a or $b Either $a or $b is true
$a || $b Either $a or $b is true

Note that the && and || opererators have higher precedence than and and or. See table below:

Evaluation Result of $e Evaluated as
$e = false || true True $e = (false || true)
$e = false or true False ($e = false) or true

Because of this it's safer to use && and || instead of and and or.