Condition for numeric table column type

New to Julia
,
1

I am importing data from database, getting DataFrame.
I am supposed to import only numeric columns, either Integer or floating point.
If the column is nullable, type is a Union of Missing & type, e.g. Union{Missing, Float64}.

Here is the code I am using currently:

function columnTypeCompare(coltype, aType)::Bool
    return (coltype === aType) || (coltype === Union{Missing, aType})
end

function isAcceptableDataType(coltype)::Bool
    for oneDataType in [Int8,Int16,Int32,Int64,Int128,UInt8,UInt16,UInt32,UInt64,UInt128,Float16,Float32,Float64]
        if columnTypeCompare(coltype, oneDataType)
            return true
        end
    end
    return false
end

But I suspect there has to be easier way to determine this, using maybe Core.Number or something like that. Any suggestion(s)?

Thank you.

2

You want the subtype operator (<:) - see docs here and here

is_acceptable(coltype) = coltype <: Union{Number, Missing}

julia> is_acceptable(Float64)
true

julia> is_acceptable(Union{Int8, Missing})
true

julia> is_acceptable(String)
false
3

Thank you!