PHP - Subtract value from 2 objects where key = is the same - php

Question

Im not sure if ive wrote the question properly but ill elaborate more on what i need.
I have two objects which i need to change to array and they have keys 1,2,3 but they have different values i need to subtract the values from the array where the keys are the same, I hope this makes sense.
Things ive tried to far
Push them both to 1 array and do the math from there (can't figure out how to do this)
use array_diff to find the difference in the arrays but didn't work.
All help appreciated any more information needed will be provided
Example Arrays:
Array 1
1 => 300.00,
2 => 300.00,
3 => 300.00
Array 2
1 => 200.00,
2 => 200.00,
3 => 200.00
Desired output
1 => 100.00,
2 => 100.00,
3 => 100.00

Answer 1

The best option for this seems to be a for loop
$arr1 = [300, 300, 300];
$arr2 = [200, 200, 200];
$arr_length = sizeof($arr1) -1;
$minus_arr = [];
for($i = 0; $i <= $arr_length; $i++){
$minus = $arr1[$i] - $arr2[$i];
array_push($minus_arr, $minus);
}
print_r($minus_arr);
I took for granted your given arrays above, it sounds like the arrays you're using are either not the same size or have strings or nulls in them so check for an int first.
<?php
$arr1 = [300, 300, 300];
$arr2 = [200, 200, 200];
$arr_length = sizeof($arr1) -1;
$minus_arr = [];
for($i = 0; $i <= $arr_length; $i++){
if(is_int($arr1[$i]) && is_int($arr2[$i])){
$minus = $arr1[$i] - $arr2[$i];
array_push($minus_arr, $minus);
}
}
print_r($minus_arr);

Answer 2

I hope I do not misunderstand your question.
My method is iterate through 2 arrays, and whenever their keys are the same, do the operation. Here is a example:
function diff($arr1, $arr2) {
$result = [];
foreach($arr1 as $key1 => $value1) {
foreach($arr2 as $key2 => $value2) {
if ($key1 == $key2) {
$result[$key1] = $value1 - $value2;
}
}
}
return $result;
}
I see there is Laravel in your tag, if you're using laravel, I'm sure that you can achieve this better with Collection. The document is here. It provides you a more 'OO' way (similar to javascript) you can operate arrays in php.

Answer 3

For an indexed array,
function diff($arr1, $arr2){
$arr3=array();
for($i=0;$i<count($arr1);$i++){
$arr3[$i]=$arr1[$i]-$arr2[$i];
}
print_r($arr3);
}
$arr1=array(300,300,300);
$arr2=array(100,100,100);
diff($arr1, $arr2);
//Displays 200, 200, 200, as expected