unique fails with column-type FixedDecimal about dataframes.jl HOT 5 CLOSED

@baumgold - it is not the type of the numbers you use but the actual value. If your values were not actually all integers things would work:

julia> df = DataFrame(A = [FixedDecimal{Int,3}(1), FixedDecimal{Int,3}(2), FixedDecimal{Int,3}(3.1)])
3×1 DataFrame
 Row │ A
     │ FixedDec…
─────┼───────────
   1 │       1.0
   2 │       2.0
   3 │       3.1

julia> unique(df)
3×1 DataFrame
 Row │ A
     │ FixedDec…
─────┼───────────
   1 │       1.0
   2 │       2.0
   3 │       3.1

Note that BigInt works:

julia> BigInt(FixedDecimal{Int,3}(1))
1

It is just the shorthand big does not work (which could be added to that package but probably its maintainers should make this decision).

@nalimilan - probably we can change big to BigInt in DataFrames.jl as a solution. OK?

@baumgold - as a temporary fix you can define big(x::FixedDecimal) = BigInt(x) in your code. It should not break anything (as big is not supported by FixedDecimal).

from dataframes.jl.

@nalimilan - we need to make a decision here. FixedPointDecimals.jl does not support conversion of integer FixedDecimal values to BigInt. I think it should, but the fact is that it does not. Our code assumes that all integers can be passed to big and be properly converted to BigInt. Do you think we should change this assumption?

@baumgold - the simplest fix would be on FixedPointDecimals.jl side if they added support for conversion of integer values to BigInt.

from dataframes.jl.

@bkamins - thanks for the quick response. I would be happy with a fix on the FixedPointDecimals.jl side. I'm not familiar enough with the purpose of Base.big to know how that should be implemented for FixedDecimal. You say that it should support conversion to BigInt but FixedDecimal is more akin like a non-lossy BigFloat than a BigInt. How should we proceed? Thanks for your help.

from dataframes.jl.

It looks like the following may be the correct implementation but I'm not confident. Thoughts?

julia> Base.big(n::FixedDecimal) = convert(BigFloat, n)

julia> Base.big(::Type{<:FixedDecimal}) = BigFloat

from dataframes.jl.

I logged JuliaMath/FixedPointDecimals.jl#91 to request that Base.big be implemented for FixedDecimal.

from dataframes.jl.