PHP Exercises: Convert the last 3 characters of a given string in upper case

Last update on April 16 2025 12:52:38 (UTC/GMT +8 hours)

24. Uppercase Last 3 Characters of String

Write a PHP program to convert the last 3 characters of a given string in upper case. If the length of the string has less than 3 then uppercase all the characters.

Sample Solution:

PHP Code :

<?php
// Define a function that modifies a string based on its length
function test($s) 
{
    // Check if the length of the string is less than 3
    return strlen($s) < 3 ? strtoupper($s) : substr($s, 0, strlen($s) - 3) . strtoupper(substr($s, strlen($s) - 3));
}

// Test the function with different strings
echo test("Python") . "\n";
echo test("Javascript") . "\n";
echo test("js") . "\n";
echo test("PHP") . "\n";
?>

Explanation:

• Function Definition:
• The test function takes a single parameter $s, a string, and modifies it based on its length.
• String Modification Logic:
• If the length of $s is less than 3 characters:
• The entire string is converted to uppercase using strtoupper.
• If the length of $s is 3 characters or more:
• The last 3 characters are converted to uppercase.
• The modified string is created by concatenating the unaltered part of $s (up to strlen($s) - 3) with the uppercase version of the last 3 characters.

Output:

PytHON
JavascrIPT
JS
PHP

Visual Presentation:

Flowchart:

For more Practice: Solve these Related Problems:

• Write a PHP script to convert the final three characters of a string to uppercase, or the entire string if its length is less than three.
• Write a PHP function to check the string length and selectively transform the last three characters to uppercase using substr and strtoupper.
• Write a PHP program to split the string into two parts and apply an uppercase transformation to the latter part conditionally.
• Write a PHP script to simulate the conversion of the last three characters by iterating over the string from the end and updating them accordingly.

PHP Code Editor:

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