Selecting data from multiple columns

Question

Mathematica has almost the following example in the documentation:

dataset = Dataset[{<|"a" -> 1, "b" -> "x", "c" -> 7|>, <|"a" -> 2, "b" -> "y","c" -> 9|>, 
 <|"a" -> "-", "b" -> "z", "c" -> "-"|>, <|"a" -> 4, "b" -> "x", "c" -> 1|>,
 <|"a" -> "-", "b" -> "y", "c" -> "-"|>, <| "a" -> 6, "b" -> "z", "c" -> 8|>}]

The first and last columns are slightly changed compared to the Mathematica documentation. To select data based on a criteria related to a column the example is:

dataset[Select[#a < 5 &]] 

What I need to have is – in its simple form:

dataset[Select[
  NumberQ[#["a"]] || NumberQ[#["b"]] || NumberQ[#["c"]] &]]

However, in the complete form there are 300+ columns, and I want to select all the datasets – but only from a subset of columns (i.e. categories/keys) – that contain numbers. I have the categories of the columns to which Select should apply in a list (in this case the list would be {"a","b","c"}).

Answer 1

You said that your dataset had over 300 columns, so perhaps the following dataset is a bit more representative:

SeedRandom[2];
dataset = Dataset @ Table[
    AssociationThread[{"a","b","c","d","e"}, RandomChoice[Range[2]~Join~{"-",u,v,w,x,y,z}, 5]],
    {10}
]

Then, if you want to select rows where there's a number in columns a, b or c, you can do the following:

With[{slots = Slot/@{"a","b","c"}},
    dataset[Select[AnyTrue[slots, NumberQ]&]]
]

Answer 2

Select[AnyTrue  @ NumberQ] @ dataset

Answer 3

I think you are asking for:

Select[NumberQ[#"a"] || NumberQ[#"b"] || NumberQ[#"c"] &]@dataset[All, {"a", "b", "c"}]

Answer 4

This may help

    Select[NumberQ[#a] & || NumberQ[#b] & || NumberQ[#c] &]@dataset