How to perform case-insensitive comparison of strings in php

Method: 1. Use the "strcasecmp(string1,string2)" statement; 2. Use the "strncasecmp(string1,string2,length)" statement; 3. Use the "strnatcasecmp(string1,string2)" statement.

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

Method 1: Use strcasecmp() Function

strcasecmp() function is not case-sensitive when comparing strings. Its syntax format is as follows:

strcasecmp(string $str1, string $str2)

Among them, $str1 and $str2 are the two characters to be compared. string.

According to the comparison result, if $str1 is less than $str2, the return value< 0; if $str1 is greater than $str2, the return value is> 0; If $str1 is equal to $str2,0is returned.

Website URLs are not case-sensitive, so we can use the strcasecmp() function to compare whether two URLs are the same. The sample code is as follows:

Output:

两个网址相同

Method 2: Use the strncasecmp() function

The strncasecmp() function compares two strings (not case-sensitive).

Syntax

strncasecmp(string1,string2,length)

Return value: This function returns:

• 0- If two strings Equality

• <0- if string1 is less than string2

• ##>0- if string1 is greater than string2

"; echo strncasecmp("Hello","hELLo",6); ?>

0 0

Method 3: Use strnatcasecmp() function

strnatcasecmp(string1,string2)

• 0- If the two strings are equal

• <0- if string1 is less than string2

• ##>0

  - if string1 is greater than string2

Example:

"; echo strnatcasecmp("10Hello world!","2Hello WORLD!"); ?>

Output:

-1 1

Natural algorithm (strnatcmp) and conventional computer string sorting algorithm ( strcmp)

"; usort($arr1,"strcmp"); print_r($arr1); echo "
"; echo "
"; echo "Natural order string comparison"."
"; usort($arr2,"strnatcmp"); print_r($arr2); ?>

Standard string comparison Array ( [0] => pic01 [1] => pic1 [2] => pic10 [3] => pic100 [4] => pic2 [5] => pic20 [6] => pic200 [7] => pic30 ) Natural order string comparison Array ( [0] => pic01 [1] => pic1 [2] => pic2 [3] => pic10 [4] => pic20 [5] => pic30 [6] => pic100 [7] => pic200 )

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