How do I get the columnar minimums in a list of arrays?
I have an array of doubles stored in a list like below. I want to get the minimum from each column. I know I can iterate over the list somehow and get the minimum. But is there an easier way to get the same thing using List.Min () from each column?
List<double[]> BoxCoords = new List<double[]>();
<!-----------------Console output of BoxCoords List------------------------------!>
8.03698858873275 | -1622.419367705 | 180.603950687759 //List Entry 1
8.03698858855283 | -1622.41905090503 | -220.203952098008 //List Entry 2
-7.70512234523364 | -1665.73116372802 | -220.204298594721 //List Entry 3
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Assuming your columns are defined by the ordinals of the wrapped arrays rather than the values in each row, here's the index
overload of method Select
to mute the data (with SelectMany
) and then regroup the data by index, after which the application Min
is a formality:
var columnMins = BoxCoords
.SelectMany(bc => bc.Select((v, idx) => new {Idx = idx, Val = v}))
.GroupBy(up => up.Idx)
.Select(grp => grp.Min(x => x.Val));
You can add .ToArray()
to the end if you need this as an arraydouble
[- 7.70512234523364, -1665.73116372802, -220.204298594721]
.NET Fiddle Demo
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for the line:
List<double[]> BoxCoords = new List<double[]>();
var result = BoxCoords.Select(x=>x.Min()).ToList();
for a column:
var result = new List<double>();
for (int i = 0; i < BoxCoords[0].Length; i++)//care! exception for jugged arrays
{
result.Add(BoxCoords.SelectMany(x => x.Skip(i).Take(1).ToList()).ToList().Min());
}
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