PHP create unique value compared to values from object - php

Question

I need to create a unique value for $total, to be different from all other values from received object. It should compare total with order_amount from object, and then if it is the same, it should increase its value by 0.00000001, and then check again through that object to see if it matches again with another order_amount. The end result should be a unique value, with minimal increase compared to the starting $total value. All values are set to have 8 decmal places.
I have tried with the following but it won't get me the result i need. What am i doing wrong?
function unique_amount($amount, $rate) {
$total = round($amount / $rate, 8);
$other_amounts = some object...;
foreach($other_amounts as $amount) {
if ($amount->order_amount == $total) {
$total = $total + 0.00000001;
}
}
return $total;
}

Answer 1

<?php
define('EPSILON',0.00000001);
$total = 4.00000000;
$other_amounts = [4.00000001,4.00000000,4.00000002];
sort($other_amounts);
foreach($other_amounts as $each_amount){
if($total === $each_amount){ // $total === $each_amount->order_amount , incase of objects
$total += EPSILON;
}
}
var_dump($total);
OUTPUT
float(4.00000003)
You may add an additional break if $total < $each_amount to make it a bit more efficient.
UPDATE
To sort objects in $other_amounts based on amount, you can use usort.
usort($other_amounts,function($o1,$o2){
if($o1->order_amount < $o2->order_amount ) return -1;
else if($o1->order_amount > $o2->order_amount ) return 1;
return 0;
});

Answer 2

Ok, here's the solution I came up with. First I created a function to deliver random objects with random totals so I could work with, unnecessary for you but useful for the sake of this test:
function generate_objects()
{
$outputObjects = [];
for ($i=0; $i < 100; $i++) {
$object = new \stdClass();
$mainValue = random_int(1,9);
$decimalValue = random_int(1,9);
$object->order_amount = "{$mainValue}.0000000{$decimalValue}";
$outputObjects[] = $object;
}
return $outputObjects;
}
And now for the solution part, first the code, then the explanation:
function unique_amount($amount, $rate) {
$total = number_format(round($amount / $rate, 8), 4);
$searchTotal = $total;
if (strpos((string) $searchTotal, '.') !== false) {
$searchTotal = str_replace('.', '\.', $searchTotal);
}
$other_amounts = generate_objects();
$similarTotals = [];
foreach($other_amounts as $amount) {
if (preg_match("/^$searchTotal/", $amount->order_amount)) {
$similarTotals[] = $amount->order_amount;
}
}
if (!empty($similarTotals)) {
rsort($similarTotals);
$total = ($similarTotals[0] + 0.00000001);
}
// DEBUG
//echo '<pre>';
//$vars = get_defined_vars();
//unset($vars['other_amounts']);
//print_r($vars);
//die;
return $total;
}
$test = unique_amount(8,1);
echo $test;
I decided to use RegEx to find the amounts that starts with the ones I provided. Since in the exercise I provided only integers with 1-9 in the last decimal case, I tracked them and added them to one array $similarTotals.
Then I sorted this array, if not empty, descending by the values, got the first item and incremented by 0.00000001.
So, finally, returning either the $total (assuming nothing was found) or the incremented first item in the array.
PS. I did not expect this code to be this big but, well...
You can see the test here: https://3v4l.org/WGThI