PHP Exercises: Create a new string which is 4 copies of the 2 front characters of a given string

Last update on May 28 2025 09:29:33 (UTC/GMT +8 hours)

8. Four Copies of First 2 Characters

Write a PHP program to create a new string which is 4 copies of the 2 front characters of a given string. If the given string length is less than 2 return the original string.

Sample Solution:

PHP Code :

<?php
// Define a function named "test" that takes a parameter $str
function test($str) 
{
    // Use a ternary operator to check if the length of $str is less than 2
    // If true, return $str as it is
    // If false, concatenate the substring from index 0 to 1 four times and return the result
    return strlen($str) < 2 ? $str : substr($str, 0, 2) . substr($str, 0, 2) . substr($str, 0, 2) . substr($str, 0, 2);
}

// Call the test function with argument "C Sharp" and echo the result
echo test("C Sharp") . "\n";

// Call the test function with argument "JS" and echo the result
echo test("JS") . "\n";

// Call the test function with argument "a" and echo the result
echo test("a") . "\n";
?>

Explanation:

Function Definition:

The function test takes one parameter, $str.

Conditional Check:

Uses a ternary operator to check if the length of $str is less than 2:

If true:

Returns $str as is (for strings with fewer than 2 characters).

If false:

Takes the first two characters (substr($str, 0, 2)) and repeats this substring four times, then returns the resulting string.

Function Calls and Output:

First Call: test("C Sharp")

Takes "C " and repeats it four times, resulting in "C C C C ".

Second Call: test("JS")

Takes "JS" and repeats it four times, resulting in "JSJSJSJS".

Third Call: test("a")

Returns "a" as the string length is less than 2.

Output:

C C C C 
JSJSJSJS
a

Visual Presentation:

PHP Basic Algorithm Exercises: Create a new string which is 4 copies of the 2 front characters of a given string.

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP function to generate a new string by repeating the first two characters of an input string four times, with fallback for short strings.
Write a PHP script to conditionally duplicate the first two characters of a string exactly four times, using substr.
Write a PHP program to replicate the first two letters of a string four times and handle edge cases with string length less than two.
Write a PHP script to check the input length and produce four concatenated copies of the first two characters, otherwise echo the original string.

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