Find nearest number

[Pig]

Hi all

 

been trying to figure out a way in PHP to find the nearest number in a group.

 

for example, given $w=5; find the number which is closest to $w from the following [2 4 6 8 10 12 14 16 18 20]?

 

I'm new to PHP, and was wondering if anyone had a script that can do the above.

 

thanks

 

 

[ignace]

$number = 5;
$nearestNumberKey = 0;
$nearestDifference = PHP_INT_MAX;

foreach ($numbers as $key => $value) {
    $difference = abs($number - $value);
    if ($difference < $nearestDifference || 0 === $difference) {
         $nearestDifference = $difference;
         $nearestNumberKey = $key;
    }
}

echo 'nearest number to ', $number, ' is ', $numbers[$nearestNumberKey];//Output: nearest number to 5 is 4

 

I realise that both 4 and 6 are candidates but as you specified key the first one he comes across wins.

[Pig]

$number = 5;
$nearestNumberKey = 0;
$nearestDifference = PHP_INT_MAX;

foreach ($numbers as $key => $value) {
    $difference = abs($number - $value);
    if ($difference < $nearestDifference || 0 === $difference) {
         $nearestDifference = $difference;
         $nearestNumberKey = $key;
    }
}

echo 'nearest number to ', $number, ' is ', $numbers[$nearestNumberKey];//Output: nearest number to 5 is 4

 

I realise that both 4 and 6 are candidates but as you specified key the first one he comes across wins.

 

 

Thanks, but I'm after some code that will compare to numbers in a list, such as [0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20].

 

So for example, if the number is 56, the answer will be 20?

 

 

[taquitosensei]

that's what $numbers is in his example

$list="4,8,15,16,23,42";
$numbers=explode("," $list); 

 

[RussellReal]

[quote author=Pig link=topic=267295.msg1260742#msg1260742

Thanks, but I'm after some code that will compare to numbers in a list, such as [0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20].

 

So for example, if the number is 56, the answer will be 20?

 

yes.. that is what you wanted is it not?

 

and if the number is 56... and two people answered 55 and 57.. who should win.. lower or higher?

[ignace]

Please do realise:

 

|| 0 === $difference

 

I'm not sure if you want this at all but this selects the key that has the same value as $number if present. And yes if you pass 56, 20 would win as it creates the lowest difference and is the highest number available in the array. Sorry if this is not what you were looking for but you must understand that the answer given is in direct correlation with the question asked.

[Pig]

OK. I am very confused. Can someone provide me the complete code, with 0,2,4,6,8,10,12,14,16,18,20 in the array?

 

Thanks.

 

 

[thebadbad]

Just specify the array before you run ignace's code:

 

$numbers = array(0,2,4,6,8,10,12,14,16,18,20);

And what you called $w is $number in his code.

[Pig]

Just specify the array before you run ignace's code:

 

$numbers = array(0,2,4,6,8,10,12,14,16,18,20);

 

Ah ha! It works! Just what I wanted.

 

Thanks all, very much appreciated