LAST UPDATED: AUGUST 4, 2021
How to convert a string to uppercase in PHP?
Answer: Using strtoupper() function
We can convert the string to uppercase using the predefined strtoupper() function. This function takes a string and returns a new string with all the alphabetic characters converted to uppercase.
The strtoupper() function does not change the string. It only converts the alphabetic characters to uppercase.
Example: Using strtoupper() function
In the given example, we have converted all the alphabetic characters of the given string to uppercase using predefined strtoupper() function.
<!DOCTYPE html>
<html>
<head>
<title>Convert a string to uppercase</title>
</head>
<body>
<?php
$str = 'Hello! welcome to studytonight';
$new_str = strtoupper($str);
echo $new_str;
?>
</body>
</html>
Output
HELLO! WELCOME TO STUDYTONIGHT
Without using any built-in function
In the above example, we have used the predefined function to convert all the alphabetic characters of the given string to uppercase. We can also convert the given string to uppercase without using any predefined function. We have created a function that will convert the characters of the string to uppercase.
Example: Without using predefined function
In the given example, we have created a function upperCase that will convert all the alphabetic characters of the string into the uppercase.
<!DOCTYPE html>
<html>
<head>
<title>Convert a string to uppercase</title>
</head>
<body>
<?php
function upperCase($str)
{
$char = str_split($str);
$result = '';
for ($i = 0; $i < count($char); $i++) {
$ch = ord($char[$i]);
if ($char[$i] >= 'a' && $char[$i] <= 'z'){
$result .= chr($ch - 32);
}
else{
$result .= $char[$i];
}
}
return $result;
}
$string = "hello! welcome to studytonight";
echo upperCase($string);
?>
</body>
</html>
Output
HELLO! WELCOME TO STUDYTONIGHT
Conclusion
In this lesson, we have learned how to convert a given string to uppercase. Here, we have discussed two approaches to convert the string to uppercase. At first, we have used the PHP predefined function strtoupper(). This function takes a string and returns a new string with all the uppercase characters. We have created a function without using the library function. The user-defined function converts all the characters of the string to uppercase.
