Compare two multidimensional arrays in PHP to sum datas - php

Question

I've two arrays:
Array A:
$rates = array(
'apple' = array(
'red' => 1.19,
'green' => 0.99,
'yellow' => 0.89
)
);
Array B:
$cart = array(
'apple' = array(
'0' => red,
'1' => green
)
);
The array B is the cart one and I need to get rates from Array A.
So:
Apple > red > 1.19
Apple > green > 0.99
Total should be 2.18.
This is what I tried:
foreach($cart as $key => $arr){
if(!in_array($key[$arr], $rates)){
$total += $rates[$key];
}
}
But it doesn't work.
What I'm missing please ?
Thanks a lot for any help.

Answer 1

You have a couple of problems. Firstly, you should be checking whether the product type from $cart exists as a key in $rates i.e.
if(!in_array($key[$arr], $rates)){
should be:
if (isset($rates[$key])) {
Secondly, once you have determined that the key does exist in $rates you then need to iterate over each of the values in $arr to get their price from $rates (using the null coalescing operator to avoid problems with values not being in the rates array):
$total = 0;
foreach ($cart as $key => $arr) {
if (isset($rates[$key])) {
foreach ($arr as $value) {
$total += $rates[$key][$value] ?? 0;
}
}
}
echo $total;
Output:
2.18
Demo on 3v4l.org

Answer 2

<?php
$rates = array(
'apple' => array(
'red' => 1.19,
'green' => 0.99,
'yellow' => 0.89
)
);
$cart = array(
'apple' => array(
'0' => 'red',
'1' => 'green'
)
);
$total = 0;
foreach($cart as $type => $items) {
if(array_key_exists($type, $rates)) {
foreach($items as $item) {
if(array_key_exists($item, $rates[$type])) {
$total += $rates[$type][$item];
}
}
}
}
echo $total;
?>