asked on

Return the closest number in a list to a given value

Hi there.

The question is simple really.

I have a list which adds a integers in a loop to it based on the outcome of certain conditions. At the end of that loop, I want to find out which is the closest number in that list to a value I already have.

How would I do that?

Example:

int myInt = 13;

myList (after going through the loop) = {1,16,20,31,2,12,4}

getClosestNumber(myInt, myList)

public int getClosestNumber(int value, List valueList)
{
run marvellous check I don't know how to do.

return int; //In this case 12. If there are two numbers (ie, if 14 is also in the list, return the lowest number).
}

Thanks in advance

SOLUTION

Mick Barry

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DanBAtkinson

ASKER

Thanks. Looking at abs in the API, how can I determine the difference between two numbers if I can only pass one?

DanBAtkinson

ASKER

D'OH.

Mick Barry

int diff = (int) Math.abs(a - b);

DanBAtkinson

ASKER

for (int i=0;i<closer.size();i++)
{
      int temp = Math.abs((Integer)closer.get(i));
      closer.remove(i);
      closer.add(temp);
}

Am I on the right track with this?

First getting them and then converting them into absolutes?

DanBAtkinson

ASKER

I'm always dealing with integers here so is there a need for Math.abs, or am I misunderstanding something?

ASKER CERTIFIED SOLUTION

Mick Barry

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DanBAtkinson

ASKER

OK.

So:

if (closer.size()>0)
{
      int bestdiff = Integer.MAX_VALUE;
      int closest = -1;
      for (int i=0;i<closer.size();i++)
      {
            int n = (Integer)(closer.get(i));
            int diff = Math.abs(departIndex - n);
            if (diff <bestdiff)
            bestdiff = diff;
      }
      System.out.println("Closest: "+bestdiff);

Does that look right to you?!

DanBAtkinson

ASKER

No. It's not right. :-)
Neither's this. :-(

System.out.println("Closest: "+info2[(Integer)closer.get(bestdiff)]);

I rewrote it to this because I need to return a value from an array (whose index corresponds to the value in the 'closer' list.

Does this make sense, and am I going in the right direction?

DanBAtkinson

ASKER

objects: Do you have any idea how I could get the correct output which corresponds to the array?

DanBAtkinson

ASKER

Never mind...

for (int i=0; i < stations.length; i++)
{
if (stations[i].contains(searchTerm))
                   {
                             System.out.println("Found: "+interchanges[i]);
                              closer.add(i);
                   }
}
                     if (closer.size()>0)
                   {
                        int bestdiff = Integer.MAX_VALUE;
                        for (int i=0;i<closer.size();i++)
                        {
                              int n = (Integer)(closer.get(i));
                              int diff = Math.abs(departIndex - n);
                              if (diff <bestdiff)
                              {
                                    bestdiff = diff;
                              }
                        }
                        int interchangeStation = (Math.max(departIndex,bestdiff)-Math.min(departIndex,bestdiff));

This provides the answer I'm looking for.

Thanks very much again objects!

Mick Barry

no worries (sorry, I stepped out for lunch)

DanBAtkinson

ASKER

lol! It's ok!

It's 05:20 here! What I wouldn't give for a Subway about now!! :-)

Mick Barry

We got spoiled with Yum Cha today :)