Sum range of int's in List<int>
C#ListSumC# Problem Overview
I reckon this will be quite trivial but I can't work out how to do it. I have a List<int>
and I want to sum a range of the numbers.
Say my list is:
var list = new List<int>()
{
1, 2, 3, 4
};
How would I get the sum of the first 3 objects? The result being 6. I tried using Enumerable.Range
but couldn't get it to work, not sure if that's the best way of going about it.
Without doing:
int sum = list[0] + list[1] + list[2];
C# Solutions
Solution 1 - C#
You can accomplish this by using Take
& Sum
:
var list = new List<int>()
{
1, 2, 3, 4
};
// 1 + 2 + 3
int sum = list.Take(3).Sum(); // Result: 6
If you want to sum a range beginning elsewhere, you can use Skip
:
var list = new List<int>()
{
1, 2, 3, 4
};
// 3 + 4
int sum = list.Skip(2).Take(2).Sum(); // Result: 7
Or, reorder your list using OrderBy
or OrderByDescending
and then sum:
var list = new List<int>()
{
1, 2, 3, 4
};
// 3 + 4
int sum = list.OrderByDescending(x => x).Take(2).Sum(); // Result: 7
As you can see, there are a number of ways to accomplish this task (or related tasks). See Take
, Sum
, Skip
, OrderBy
& OrderByDescending
documentation for further information.
Solution 2 - C#
Or just use Linq
int result = list.Sum();
To sum first three elements:
int result = list.GetRange(0,3).Sum();