PHP Exercises: Check if a given string starts with a given substring

Last update on April 19 2025 11:50:14 (UTC/GMT +8 hours)

95. Check String Starts With Substring

Write a PHP program to check if a given string starts with a given substring.

Sample Solution:

PHP Code:

<?php
// Licence: https://bit.ly/2CFA5XY

// Function definition for 'startsWith' that takes a haystack string and a needle string as parameters
function startsWith($haystack, $needle)
{
    // Use 'strpos' to find the position of the needle in the haystack
    // Check if the position is at the beginning (index 0) of the haystack
    return strpos($haystack, $needle) === 0;
}

// Call 'startsWith' with a haystack string and a needle string, then display the result using 'print_r'
print_r(startsWith('Hi, this is me', 'Hi'));

?>

Explanation:

Function Definition:

The startsWith function takes two parameters:

$haystack: the main string in which to search.
$needle: the substring to check if it appears at the beginning of $haystack.

Check Start Position:

The function uses strpos($haystack, $needle) to find the position of $needle within $haystack.
It then checks if $needle is found at the very beginning (position 0) of $haystack.

Return Result:

If $needle is at the start of $haystack, the function returns true.
Otherwise, it returns false.

Function Call and Output:

startsWith('Hi, this is me', 'Hi') checks if 'Hi' is at the beginning of 'Hi, this is me'. Result: true (output as 1 with print_r).

Output:

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to determine if a given string starts with a specific substring using substr comparison.
Write a PHP function to check whether the first few characters of a string match a target prefix.
Write a PHP script to use strpos or regex to verify if a string begins with the specified sequence.
Write a PHP script to return a boolean indicating whether the initial segment of a string equals a given substring.

PHP Code Editor:

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