Associative arrays

<?php
$units = ["Nairobi" => 12, "Mombasa" => 8];
echo $units["Nairobi"], PHP_EOL;

<?php
$row = ["city" => "Kisumu", "units" => 5];
echo $row["city"], PHP_EOL;
echo $row["units"], PHP_EOL;

<?php
$kiosks = ["Nairobi" => 12, "Kisumu" => 5];
$kiosks["Eldoret"] = 3;
echo implode(",", array_keys($kiosks)), PHP_EOL;

<?php
echo array_sum(["Nairobi" => 12, "Nakuru" => 4]), PHP_EOL;