PHP Exercises: Create a new string of length 2 starting at the given index of a given string

Last update on May 28 2025 13:05:00 (UTC/GMT +8 hours)

73. Substring of Length 2 at Given Index

Write a PHP program to create a new string of length 2 starting at the given index of a given string.

Sample Solution:

PHP Code :

<?php
// Define a function named 'test' that extracts a substring of length 2 starting from the specified index in the input string
// If the index + 2 exceeds the length of the string, extract the first 2 characters
function test($s1, $index)
{ 
   // Use substr to extract a substring of length 2 starting from the specified index
   // If the index + 2 exceeds the length of the string, extract the first 2 characters
   return $index + 2 <= strlen($s1) ? substr($s1, $index, 2) : substr($s1, 0, 2);
}

// Test the 'test' function with different strings and index values, then display the results using echo
echo test("Hello", 1)."\n";
echo test("Python", 2)."\n";
echo test("on", 1)."\n";
?>

Explanation:

Function Definition:

A function named test is defined with two parameters:

$s1: the input string.
$index: the starting position for extracting a substring.

Substring Extraction:

The function uses a conditional expression to decide which substring to extract:

If $index + 2 is less than or equal to the length of $s1, substr($s1, $index, 2) extracts two characters from the specified index.
If $index + 2 exceeds the length of $s1, substr($s1, 0, 2) extracts the first two characters of the string.

Output:

el
th
on

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to extract a substring of length 2 starting at a specified index from a given string.
Write a PHP function to validate the given index and return exactly two characters from that position.
Write a PHP program to use substr to pick a 2-letter slice from a string at the user-defined index.
Write a PHP script to implement error handling while extracting a two-character segment from a provided index.

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