PHP Exercises: Create a new string of length 2, using first two characters of a given string

Last update on May 28 2025 13:04:59 (UTC/GMT +8 hours)

75. New String of Length 2 with Padding

Write a PHP program to create a new string of length 2, using first two characters of a given string. If the given string length is less than 2 use '#' as missing characters.

Sample Solution:

PHP Code :

<?php
// Define a function named 'test' that modifies the input string based on its length
function test($s1)
{ 
  // Check if the length of the string is greater than or equal to 2
  if (strlen($s1) >= 2)
     {
       // If true, extract the first two characters from the string
       $s1 = substr($s1, 0, 2);
      }
  // If the length is greater than 0 but less than 2
  else if (strlen($s1) > 0)
      {
       // Extract the first character and concatenate "#" to it
       $s1 = substr($s1, 0, 1) . "#";
      }
  // If the length is 0
  else
      {
       // Set the string to "##"
       $s1 = "##";
      }
   // Return the modified string
   return $s1;
}

// Test the 'test' function with different strings, then display the results using echo
echo test("Hello")."\n";
echo test("Python")."\n";
echo test("a")."\n";
echo test(" ")."\n";
?>

Explanation:

Function Definition:

The test function is defined with a single parameter:

$s1: the input string.

String Modification Based on Length:

The function has three cases based on the length of $s1:

If the length is 2 or more:

Extracts the first two characters of $s1 using substr($s1, 0, 2).

If the length is 1:

Extracts the first character and appends a "#" to it, making $s1 = substr($s1, 0, 1) . "#".

If the length is 0:

Sets $s1 to "##".

Return Value:

Returns the modified $s1 based on the above conditions.

Output:

He
Py
a#
 #

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to create a string using the first two characters of an input, padding with '#' if necessary when the string is too short.
Write a PHP function to conditionally append '#' characters to an input if its length is less than 2, then output exactly two characters.
Write a PHP program to check the length of a string and output either the first two letters or the string supplemented with '#'.
Write a PHP script to simulate string padding for inputs of length 0 or 1 to guarantee a two-character result.

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