how to convert lower case to upper in php code example

Example 1: php string to uppwe

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

echo $uppercase;
// THIS IS LOWER CASE

Example 2: 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 3: convert string to lowercase in php

/* strtolower() function converts  string to lowercase. */
<?php
echo strtolower("Hello WORLD 123");
?>
// Output:hello world 123

Example 4: php convert to lowercase

<?php
echo strtolower("Convert THIS TEXT ALL TO LOWER CASE");
?>