Sort a 2D Points List (first by X and then Y)
14,265
Solution 1
This should work better:
class PointComparer : IComparer<Point>
{
public int Compare(Point first, Point second)
{
if (first.X == second.X)
{
return first.Y - second.Y;
}
else
{
return first.X - second.X;
}
}
}
If the X values are different, it will use the Y value for sorting. This is different from your code, where X values will be used if the Y values are the same.
As others have mentioned, if you can use Linq, you should use the OrderBy
and ThenBy
extension methods:
pointsList.OrderBy(p => p.X).ThenBy(p => p.y)
Solution 2
Could you not use OrderBy -> ThenBy?
http://msdn.microsoft.com/en-us/library/bb534743.aspx
Author by
Mikos
Updated on June 13, 2022Comments
-
Mikos almost 2 years
I am trying to sort a List of 2D Points first by x co-ordinate and then by y co-ordinate. I implemented the IComparer interface as follows:
class PointComparer : IComparer<Point> { public int Compare(Point x, Point y) { if (x.Y != y.Y) { return x.Y - y.Y; } else { return x.X - y.X; } } }
And then call my sorting as follows:
pointsList.Sort(new PointComparer());
For some reason the list doesn't sort. Surely is something very simple and silly, but stuck on this for quite a while....TIA