CODEWITHSUNDEEP
c#linqfiltering
FrostyFire
FrostyFire

Reputation: 3258

C# Linq, find lowest value in List<int> between two numbers

I know this question has been asked before, but the other questions are only about finding the CLOSEST. I dont want that. I need the LOWEST between two values. For example if this is the list: Code from How to get the closest number from a List<int> with LINQ?:

List<int> numbers = new List<int>();
numbers.Add(2);
numbers.Add(5);
numbers.Add(7);
numbers.Add(10)

and the number to find is 9, I want it to return the 7 item, not 10 even though its closer. This code finds the closest, but any time I change it to find the lowest in the range it breaks for other situations where the inputted number is one of the numbers in the list(for example 7 or 10):

list.Aggregate((x,y) => Math.Abs(x-number) < Math.Abs(y-number) ? x : y);

How do I alter that code to support what I need to do?

I know I could use binarysearch... I don't want to use that, I want to use linq if possible.

Upvotes: 1

Views: 3068

Answers (3)

bto.rdz
bto.rdz

Reputation: 6720

even @danielnixon answer is good, this uses agregate

int? closerLow = (int?) list.Aggregate((x,y) => Math.Abs(x-number) < Math.Abs(y-number) 
                     ? (x > number ? y : x ) 
                     : (y > number ? x : y));

if (closerLow > number) closerLow = null;

Upvotes: 1

GeekzSG
GeekzSG

Reputation: 963

If you have to consider cases where the list will not any number closest, the code would look like,

    private static int? GetClosest(List<int> numbers, int number)
    {
        var shorterEnumerable = numbers.Where(x => x <= number);
        var shorterArray = shorterEnumerable as int[] ?? shorterEnumerable.ToArray();
        if (shorterArray.Length > 1)
            return shorterArray.Max();

        return null;
    }

Upvotes: 1

danielnixon
danielnixon

Reputation: 4268

var numbers = new List<int> { 2, 5, 7, 10 };
var seven = numbers.Where(n => n <= 9).Max();

Upvotes: 8

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