Julia: tryparse should have argument to return missing

[scls19fr]

Hello,

Following https://github.com/JuliaData/DataFrames.jl/issues/1854 I wonder if tryparse implementation shouldn't have an argument to output missing instead of nothing.

So it will be possible to simply do

julia> using DataFrames
julia> df = DataFrame(:A=>["", "2", "3"], :B=>[1.1, 2.2, 3.3])
3×2 DataFrame
│ Row │ A      │ B       │
│     │ String │ Float64 │
├─────┼────────┼─────────┤
│ 1   │        │ 1.1     │
│ 2   │ 2      │ 2.2     │
│ 3   │ 3      │ 3.3     │
julia> df.A = tryparse.(Int, df.A, missing)
3-element Array{Union{Missing, Int64},1}:
  missing
 2
 3
julia> df
3×2 DataFrame
│ Row │ A       │ B       │
│     │ Int64⍰  │ Float64 │
├─────┼─────────┼─────────┤
│ 1   │ missing │ 1.1     │
│ 2   │ 2       │ 2.2     │
│ 3   │ 3       │ 3.3     │

Your opinion?

Kind regards

[KristofferC]

The value is not missing here. If you want missing just wrap tryparse in a function that transform nothing to missing.

[quinnj]

Yeah, this should be as simple as doing mytryparse(T, str) = something(tryparse(T, str), missing)

[scls19fr]

Maybe the discussion should continue in https://github.com/JuliaData/Missings.jl/issues/61