PHP Array Exercises : Get the largest key in an array

Last update on May 30 2025 13:14:54 (UTC/GMT +8 hours)

16. Get the Largest Key in an Array

Write a PHP script to get the largest key in an array.

Sample Solution:

PHP Code:

<?php
// Define an associative array $ceu with countries as keys and their capitals as values
$ceu = array(
    "Italy" => "Rome",
    "Luxembourg" => "Luxembourg",
    "Belgium" => "Brussels",
    "Denmark" => "Copenhagen",
    "Finland" => "Helsinki",
    "France" => "Paris",
    "Slovakia" => "Bratislava",
    "Slovenia" => "Ljubljana",
    "Germany" => "Berlin",
    "Greece" => "Athens",
    "Ireland" => "Dublin",
    "Netherlands" => "Amsterdam",
    "Portugal" => "Lisbon",
    "Spain" => "Madrid",
    "Sweden" => "Stockholm",
    "United Kingdom" => "London",
    "Cyprus" => "Nicosia",
    "Lithuania" => "Vilnius",
    "Czech Republic" => "Prague",
    "Estonia" => "Tallin",
    "Hungary" => "Budapest",
    "Latvia" => "Riga",
    "Malta" => "Valetta",
    "Austria" => "Vienna",
    "Poland" => "Warsaw"
);

// Use 'max' and 'array_keys' functions to find the maximum key in the associative array
$max_key = max(array_keys($ceu));

// Echo the maximum key
echo $max_key . "\n";

?>

Output:

United Kingdom

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to iterate through an associative array and determine the largest key using custom comparison logic.
Write a PHP function that accepts an associative array and returns the maximum key by sorting the keys numerically or lexicographically.
Write a PHP program to extract the keys of an associative array and use max() to find the largest one, then display it.
Write a PHP script to implement a manual loop comparing keys of an array to determine the highest one without built-in functions.

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