Comparing two arrays php with a third array - php

Question

I have two arrays with the year's results.
array A (
[a] => '150'
[b] => '200'
[c] => '300'
[d] => '1000'
[e] => '350'
[f] => '1000'
)
array B (
[a] => '500'
[b] => '400'
[d] => '1000'
[f] => '1000'
)
I need to compare the growth results between the two building another array, to show it in a html table. Ex:
[a] => 233%
[b] => 100%
...
I have a array identifying the indexes that are not present on array b.
array c = ('c', 'e');
The thing is, I need the row C and E to still be displayed on the table. But on the iteration, how can i just jump the line with this indexes that have 0 value avoiding calculation 300 by 0 and putting a message instead?

Answer 1

You can iterate the first array and check the next one values:
$arrayA = [
'a' => '150',
'b' => '200',
'c' => '300',
'd' => '1000',
'e' => '350',
'f' => '1000',
];
$arrayB = [
'a' => '500',
'b' => '400',
'd' => '1000',
'f' => '1000',
];
$result = [];
foreach ($arrayA as $key => $value) {
if(isset($arrayB[$key])) {
$result[$key] = round($arrayB[$key] * 100 / $value, 2);
} else {
$result[$key] = 'some value when empty';
}
}
var_dump($result);
Output:
array(6) {
["a"]=>
float(333.33)
["b"]=>
float(200)
["c"]=>
string(21) "some value when empty"
["d"]=>
float(100)
["e"]=>
string(21) "some value when empty"
["f"]=>
float(100)
}

Answer 2

You could loop through array A and check if the key of array A exists in array B using array_key_exists and then calculate the growth percentage:
$arrayA = [
'a' => '150',
'b' => '200',
'c' => '300',
'd' => '1000',
'e' => '350',
'f' => '1000'
];
$arrayB = [
'a' => '500',
'b' => '400',
'd' => '1000',
'f' => '1000'
];
$arrayC = [];
foreach($arrayA as $keyA => $valueA) {
if (array_key_exists($keyA, $arrayB)) {
$arrayC[$keyA] = floor((($arrayB[$keyA] - $valueA) / $valueA ) * 100) . "%";
continue;
}
$arrayC[$keyA] = "No match";
}
Result
Array
(
[a] => 233%
[b] => 100%
[c] => No match
[d] => 0%
[e] => No match
[f] => 0%
)
Demo

Answer 3

If you want a more flexible solution where you can check for both values of the two arrays (i.e. do not base the comparison keys on a single array) and have the possibility to expand it for more than two arrays (it may be useful to others who do not have your same goal).
Fetch the keys of the two array with array_keys and use array_unique in order to avoid duplicate keys values.
<?php
$array_a = [
'a' => 150,
'b' => 200,
'c' => 300,
'd' => 1000,
'e' => 350,
'f' => 1000
];
$array_b = [
'a' => 500,
'b' => 400,
'd' => 1000,
'f' => 1000
];
$keys_a = array_keys($array_a);
$keys_b = array_keys($array_b);
$keys = array_unique(array_merge($keys_a, $keys_b));
$result = [];
foreach ($keys as $key)
{
if (isset($array_a[$key]) && isset($array_b[$key]))
{
$result[$key] = round((($array_b[$key] - $array_a[$key]) / $array_a[$key]) * 100);
}
else
{
$result[$key] = "missing key in one of the two arrays";
}
}
Output:
Array
(
[a] => 233
[b] => 100
[c] => missing key in one of the two arrays
[d] => 0
[e] => missing key in one of the two arrays
[f] => 0
)