Sort tuple list in C#

Question

Working on C#.NET. I have this list:

List<Tuple<string, float>> sort = new List<Tuple<string, float>>();

I want to sort this list by the float value. Eg if the list is like this:

a,45
b,2
s,32
se,83.21
te,84
s3,9.5
f,7

I want it to be sorted in a descending order, like this:

te,84
se,83.21   
a,45
s,32
s3,9.5
f,7
b,2

Answer 1

If you want to sort the list inplace, you can use the Sort method that takes Comparison<T> argument.

To sort by the Tuple.Item2 in ascending order, you can use

sort.Sort((a, b) => a.Item2.CompareTo(b.Item2));

To sort in descending order, just swap a and b:

sort.Sort((a, b) => b.Item2.CompareTo(a.Item2));

Answer 2

Here is an easy way to sort the list:

sort = sort.OrderByDescending(s => s.Item2).ToList();

Answer 3

You wouldn't sort the list - you'd create a new list which contains the same items, but is sorted.

var sorted = sort.OrderByDescending(t => t.Item2).ToList();

Answer 4

If you don't want to create a new list you can use the IComparer<> interface to create a customer comparer.

public class MyCompare : IComparer<Tuple<string, float>>
{
    public int Compare(Tuple<string, float> x, Tuple<string, float> y)
    {
        return y.Item2.CompareTo(x.Item2);
    }
}

... then you would use it like this ...

sort.Sort(new MyCompare());