Get Max and Min in a single LINQ query

Question

I have a set of objects with two properties, A and B. I'd like to get the Min of A and the Max of B.

eg

var minA = objects.Min(o => o.A);
var maxB = objects.Max(o => o.B);

Using LINQ query syntax, is there a way to do this so it only passes over the set once?

Desired outcome would be an anonymous type (eg, results.MinA = x, results.MaxB = y)

Answer 1

Min and Max are both aggregates. The general linq aggregate function is Aggregate

Assuming property A is an integer, and B is a string, you could write something like this:

objects.Aggregate(
    new {
        MinA = int.MaxValue,
        MaxB = string.Empty
    },
    (accumulator, o) => new {
        MinA = Math.Min(o.A, accumulator.MinA),
        MaxB = o.B > accumulator.MaxB ? o.B : accumulator.MaxB
    });