PHP Exercises: Create a new string which is n copies of the the first 3 characters of a given string

Last update on December 20 2024 10:20:10 (UTC/GMT +8 hours)

Write a PHP program to create a new string which is n (non-negative integer) copies of the the first 3 characters of a given string. If the length of the given string is less than 3 then return n copies of the string.

Sample Solution:

PHP Code :

<?php
// Define a function that repeats the front part of a string $n times
function test($s, $n)
{
    // Initialize an empty string to store the result
    $result = "";

    // Define the number of characters from the front of the string to repeat
    $frontOfString = 3;

    // Adjust $frontOfString if it exceeds the length of the input string
    if ($frontOfString > strlen($s)) {
        $frontOfString = strlen($s);
    }

    // Extract the front part of the string
    $front = substr($s, 0, $frontOfString);

    // Concatenate the front part to the result $n times
    for ($i = 0; $i < $n; $i++) {
        $result = $result . $front;
    }

    // Return the final result
    return $result;
}

// Test the function with different inputs
echo test("Python", 2) . "\n";
echo test("Python", 3) . "\n";
echo test("JS", 3) . "\n";
?>

Explanation:

• Function Definition:
• The test function takes two parameters: $s (a string to work with) and $n (the number of times to repeat the front part of the string).
• Initialize Result Variable:
• An empty string variable $result is initialized to accumulate the repeated front part of the string.
• Define Front Part Length:
• A variable $frontOfString is set to 3, indicating the number of characters to take from the beginning of the string.
• Adjust Front Part Length If Needed:
• If the length of $s is shorter than 3, $frontOfString is adjusted to the length of $s to avoid out-of-bounds errors.
• Extract Front Part of the String:
• Using substr, the front portion (either the first three characters or the full string if it’s shorter than three characters) is extracted into $front.
• Repeat the Front Part:
• A for loop runs $n times, concatenating $front to $result in each iteration.
• Return Result:
• The function returns the accumulated $result.

Output:

PytPyt
PytPytPyt
JSJSJS

Visual Presentation:

Flowchart:

PHP Code Editor:

Click to Open Editor

Contribute your code and comments through Disqus.

Previous: Write a PHP program to create a new string which is n (non-negative integer) copies of a given string.
Next: Write a PHP program to count the string "aa" in a given string and assume "aaa" contains two "aa".