查找n元组的最小值和最大值？

Question

I have a tuple representing xy coordinates. These tuples are then used to define the sizes of two boxes as seen here . Then I would like to create a bounding box surrounding these two boxes which then has the two points; one for the bottom left and one for the top right. The bot-right point would have the x-coordinate min(p1.x, p3.x), y-coordinate = min(p1.y, p3.y). The top-right point would have x=max(p2.x, p4.x), y=max(p2.y, p4.y) if I am not mistaken.

The main problem that I have to is to find a way to get the min and max of n-tuples and derive these two new points for the outer bounding box in a rather pretty way.

Answer 1

It is difficult to give a useful answer without knowing a bit more about the context and without seeing any sample code of what you have so far. However, your four points are presumably four tuples:

let p1 = (0, 5)
let p2 = (10, 15)
let p3 = (5, 0)
let p4 = (15, 10)

Now, if you just want to get the minimal X and Y values, you can create a list of all the points and use minBy :

let ps = [p1; p2; p3; p4] 
let minX = ps |> List.minBy fst
let minY = ps |> List.minBy snd

Answer 2

In something similar to @TomasPetricek's answer, you can use LINQ in C#:

var p1 = (0, 5);
var p2 = (10, 15);
var p3 = (5, 0);
var p4 = (15, 10);

var ps = new[] { p1, p2, p3, p4 };

var minX = ps.Select(p => p.Item1).Min();
var minY = ps.Select(p => p.Item2).Min();

Abusing the LINQ Aggregate method, you can compute the answer at once:

var ps = new[] { p2, p3, p4 };

var ans = ps.Aggregate((p1, p1), (rect, p) => ((Math.Min(rect.Item1.Item1,p.Item1),Math.Min(rect.Item1.Item2,p.Item2)),
                                               (Math.Max(rect.Item2.Item1,p.Item1),Math.Max(rect.Item2.Item2,p.Item2))));