php changing work to uppercase code example

Example 1: php uppercase

//string to all uppercase
$string = "String with Mixed use of Uppercase and Lowercase";
//php string to uppercase
$string = strtoupper($string);
// = "STRING WITH MIXED USE OF UPPERCASE AND LOWERCASE"

Example 2: php change sting to caps

$lowercase = "this is lower case";
$uppercase = strtoupper($lowercase);

echo $uppercase;