Changing the case of a string

Converting case of a sentence of strings: mb_convert_case()

You can convert the case of a sentence with the mb_convert_case() function.

You have multiple modes for influencing the way you want to change the case, and some of them are pretty similar:

$modes = [
    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
];

For example, you can convert all chars in upper case with MB_CASE_UPPER, or you can convert all chars in lower case with MB_CASE_LOWER, or you can obtain words with the first letter upper case and all others with lower case like “Hello, How Are You?”

foreach ($modes as $mode) {
    echo mb_convert_case('Hello, HOW are yOu?', $mode), PHP_EOL;
}
/*
HELLO, HOW ARE YOU?
hello, how are you?
Hello, How Are You?
hello, how are you?
HELLO, HOW ARE YOU?
hello, how are you?
Hello, How Are You?
hello, how are you?
*/