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

Last update on December 20 2024 10:24:28 (UTC/GMT +8 hours)

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:

1

Flowchart:

PHP Code Editor:

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