Working with text case of PHP string

PHP provides number of functions to work with the case of the string. All these functions take the source string as their argument and return the modified string. The original source string will not be modified by any of these functions.

The PHP functions for working on case are:
strtolower() - Converts the entire string to lowercase

strtoupper() - Converts the entire string to uppercase

ucfirst() - Converts the first letter of the sentence to uppercase

ucwords() - Converts the first letter of every word in string to uppercase

<?php
//usage of ucfirst() function
$str = "i am samar";
$str = ucfirst($str);
echo $str;
?>

Output: I am samar

<?php
//usage of ucwords() function
$str = "i am samar";
$str = ucwords($str);
echo $str;
?>

Output: I Am Samar

<?php
//usage of strtoupper() function
//similarly use strtolower() function
$str = "i am samar";
$str = strtoupper($str);
echo $str;
?>

Output: I AM SAMAR