PHP mb_convert_case() Function

The mb_convert_case() function is an inbuilt function in PHP that is used to perform case folding on the string and converted it into the specified mode of string. 

Syntax:

string mb_convert_case(
    string $string, 
    int $mode, 
    string $encoding = null
)

Parameters: This function accepts three parameters that are described below:

• $string: This parameter defines the string that needs to convert into a specified mode.
• $mode: This parameter holds the mode of conversion. The mode of conversion can be:
  • MB_CASE_UPPER
  • MB_CASE_LOWER
  • MB_CASE_TITLE
  • MB_CASE_FOLD
  • MB_CASE_UPPER_SIMPLE
  • MB_CASE_LOWER_SIMPLE
  • MB_CASE_TITLE_SIMPLE
  • MB_CASE_FOLD_SIMPLE
• $encoding: This parameter describes the character encoding. If this parameter value is omitted or null, the internal character encoding value will be used.

Return Value: This parameter returns the case folded version of the string converted into the specified mode.

Example 1: The following code demonstrates the PHP mb_convert_case() function.

PHP

<?php

    // Declare a string
    $str = "welcome to geeksforgeeks";

    // Convert given string into upper
    // case using "UTF-8" encoding
    $upperCase = mb_convert_case(
          $str, MB_CASE_UPPER, "UTF-8");

    // Print upper case string
    echo $upperCase;

    // Convert string into lower case
    // using "UTF-8" encoding
    $lowerCase = mb_convert_case(
          $upperCase, MB_CASE_LOWER, "UTF-8");

    // Print lower case string
    echo "\n" . $lowerCase;

?>

Output

WELCOME TO GEEKSFORGEEKS
welcome to geeksforgeeks

Example 2: The following code demonstrates another example of the PHP mb_convert_case() function.

PHP

<?php

    // Declare a string
    $str = "welcome to geeksforgeeks";

    // Convert given string into case
    // title using "UTF-8" encoding
    $upperCase = mb_convert_case(
          $str, MB_CASE_TITLE, "UTF-8");

    // Print upper case string
    echo $upperCase;

    // Convert string into case upper
    // simple using "UTF-8" encoding
    $lowerCase = mb_convert_case(
          $upperCase, MB_CASE_UPPER_SIMPLE, "UTF-8");

    // Print lower case string
    echo "\n" . $lowerCase;
?>

Output

Welcome To Geeksforgeeks
WELCOME TO GEEKSFORGEEKS

Reference: https://www.php.net/manual/en/function.mb-convert-case.php