元素的分组和排序

Question

public class RebarUnique{    public Rebar MRebar { get; set; }    public Point2d Point2d { get; set; }}public class Rebar{    public string Number { get; set; }    public int Type { get; set; }    public int Fi { get; set; }}我有清单：List<RebarUnique> rebarUnique;[{{Number: 1, Type: 1, Fi: 12}, (0,0)},{{Number: 1, Type: 1, Fi: 12}, (0,10)},{{Number: 2, Type: 1, Fi: 12}, (15,18)},{{Number: 3, Type: 1, Fi: 12}, (25,34)},{{Number: 1, Type: 1, Fi: 12}, (25,34)},{{Number: 3, Type: 1, Fi: 12}, (13,38)}]我想得到一个清单：通过...分组 Number按Point2d( Y coordinate)排序返回Number具有最低值的列表 ( )Y coordinate

Answer 1

这样的事情应该工作：

var rebarUniqueL = rebarUnique
    .GroupBy(x => x.MRebar.Number)
    .Select(x => x.OrderBy(y => y.Point2d.Y).First())
    .ToList();

Answer 2

rebarUnique.OrderBy(x => x.Point2d.Y) // Order the items by Y

    .GroupBy(x => x.MRebar.Number) //Then group them by number, within each group the items are still sorted by Y

    .Select(g => new {Number = g.Key, Item = g.First()) // get lowest Y for each number

    .ToList();

输出：

Number   Item    

1        {{Number: 1, Type: 1, Fi: 12}, (0,0)}

2        {{Number: 2, Type: 1, Fi: 12}, (15,18)}

3        {{Number: 3, Type: 1, Fi: 12}, (25,34)},