compare two amount from one array with a giving amount an bring the key of the higher one

Question

i have and amount to compare with the prices in the array and bring one id result.

let say the amount is 113, in this case a need to pick id 31 as result because i have to take the one closer but the biggest one or the exact one in case be like 110 or 115 using php 5.3 to 7.1

$prices = array(
  array('id' => '28','price' =>100 ),
  array('id' => '29','price' =>105 ),
  array('id' => '30','price' =>110 ),
  array('id' => '31','price' =>115 ),
  array('id' => '32','price' =>120 ),
  array('id' => '33','price' =>125 ),
  array('id' => '34','price' =>130 )
);

i search on internet i try some array function. i found this article here, but does not meet my need. text

How exactly does your reference Stack Overflow page NOT help you? Where is your coding attempt? — mickmackusa, Apr 10 '23 at 06:48

Aksen P · Answer 1 · 2023-04-10T00:59:24.327

The easiest way is using the next foreach loop:

$amount = 113;
$result_id = null;
$take_next = false;

foreach ($prices as $item) {
    if ($item['price'] < $amount) {
        $take_next = true;
    } elseif ($item['price'] == $amount){
        $result_id = $item['id'];
        break;
    } else {
        if ($take_next){
            $result_id = $item['id'];
        }
        break;
    }  
}

echo $result_id;

Note: the array must be ordered by amount. If amount is > 130, then result_id will be a null.

Demo

Update:

Covered case when amount is < 100.

Demo

score 0 · Answer 2 · answered Apr 09 '23 at 21:13

0

usort($prices, fn($p1, $p2) => $p1['price'] <=> $p2['price']);
$result = array_values(array_filter($prices, fn($p) => $p['price'] >= 113))[0];

Note that the <=> operator is only available in PHP 7 or higher. It can be replace with:

usort($prices, fn($p1, $p2) => $p1['price'] < $p2['price'] ? -1 : ( $p1['price'] > $p2['price'] ? 1 : 0));

answered Apr 09 '23 at 21:13

lukas.j

6,453
2
5
24

This does not look efficient. – mickmackusa Apr 10 '23 at 06:49

score 0 · Answer 3 · answered Apr 10 '23 at 06:00

Well, to get the nearest highest for a given amount:

Just run a loop and check if the current price is greater than or equal to the amount.
Now, check if the difference between current price and amount is less than the previously recorded difference. If yes, update the result, else move ahead for the next value.

Snippet:

<?php

function getNearestHighest($prices, $amount){
    $resullt = null;
    $diff = PHP_INT_MAX;
    
    foreach($prices as $p){
        if($p['price'] >= $amount){
            if(abs($p['price'] - $amount) < $diff){
                $result = $p;
                $diff = abs($p['price'] - $amount);
            }
        }
    }
    
    if(is_null($result)) throw new \Exception("No nearest highest amount exists!");
    return $result;
}

Driver code:

<?php

try{
    print_r(getNearestHighest($prices, 113));
}catch(\Exception $e){
    // whatever you wish to do
}

Online Demo

Note: This will get the result in O(n) time and doesn't require the data set to be in a sorted state in the first place.

compare two amount from one array with a giving amount an bring the key of the higher one

3 Answers3