The strncasecmp() function is a built-in function in PHP and is used to compare two given strings. It is case-insensitive. This function is similar to strcasecmp(), the only difference is the provision to specify the number of characters to be used from each string for the comparison.
Syntax:
strncasecmp($string1, $string2, $length)
Parameters: This function accepts two parameters as shown in the above syntax and are described below:
- $string1, $string2: These parameters specifies the strings to be compared.
- $length: It specifies the number of characters from each string to be used in the comparison. This parameter is mandatory
Return Value: This function returns an integer based on the conditions as described below:
- strncasecmp() returns 0 – if the two strings are equal.
- strncasecmp() returns <0 – if string1 is less than string2
- strncasecmp() returns >0 – if string1 is greater than string2
Examples:
Input : string1 = "Hello", string2 = "hEllo", length = 6 Output : 0 Input : string1 = "Geeks", string2 = "Gfg", length = 3 Output : -1 Input : string1 = "Nerd", string2 = "Geeks", length = 4 Output : 7
Below programs illustrate the strncasecmp() function in PHP:
Program 1: When the two strings are identical:
<?php   $str1 = "Geeks for Geeks "; $str2 = "Geeks for Geeks ";   // Both the strings are equal $test=strncasecmp($str1, $str2, 16 );   echo "$test";   ?> |
Output :
0
Program 2 : When first string greater than the second string:
<?php   // Input strings $str1 = "Geeks for Geeks "; $str2 = "Geeks for ";   $test=strncasecmp($str1, $str2, 16 );   // In this case the second string is smaller echo "$test";   ?> |
Output:
6
Program 3: First string is smaller than the second string:
<?php   // Input Strings $str1 = "Geeks for "; $str2 = "Geeks for Geeks ";   $test=strncasecmp($str1, $str2, 16 );   // In this case the first string is smaller echo "$test";   ?> |
Output:
-6
Program 4: This program illustrates the case-insensitivity of the function:
<?php   // Input Strings $str1 = "GEEKS FOR GEEKS "; $str2 = "Geeks for Geeks ";   // Both the strings are equal $test=strncasecmp($str1, $str2, 16 );   echo "$test";   ?> |
Output:
0
Program 5: Two strings are of equal length but contain a different character. In such a case the difference between ASCII value of the two characters is displayed. The function returns a positive value if the character in string1 has a greater ASCII value and negative if the character in string2 has a greater ASCII value.
<?php   // Input Strings $str1 = "Good"; $str2 = "Goon";   $test1 = strncasecmp($str1, $str2, 4 );   // Second string has a character // with higher ASCII value echo "$test1";   echo "\n";   $test2 = strncasecmp($str2, $str1, 4 );   // First string has a character // with higher ASCII value echo "$test2";   ?> |
Output:
-10 10
Reference:
http://php.net/manual/en/function.strncasecmp.php
