DataFramesMeta Arthimetic

New to Julia
1

How do you add/subtract/muiltply/divide a column in my dataframe by a scalar?

@> begin
     dat
    @transform(new_col=:x ./365)

throws an error:

MethodError: no method matching /(::Symbol, ::Int64)

thoughts? just want to convert days to years. Had Similar trouble with +, -, etc.

2

Do you want to do something like this:

julia> using DataFrames

julia> df = DataFrame(a = rand(3), b = rand(3))
3×2 DataFrame
│ Row │ a        │ b        │
│     │ Float64  │ Float64  │
├─────┼──────────┼──────────┤
│ 1   │ 0.254205 │ 0.843809 │
│ 2   │ 0.454499 │ 0.106612 │
│ 3   │ 0.646103 │ 0.286037 │

julia> df.a ./= 365
3-element Array{Float64,1}:
 0.0006964531670979474
 0.0012452038656085495
 0.0017701452273107896

julia> df
3×2 DataFrame
│ Row │ a           │ b        │
│     │ Float64     │ Float64  │
├─────┼─────────────┼──────────┤
│ 1   │ 0.000696453 │ 0.843809 │
│ 2   │ 0.0012452   │ 0.106612 │
│ 3   │ 0.00177015  │ 0.286037 │

or

julia> using DataFramesMeta

julia> df = @transform df c = :b ./ 365
3×3 DataFrame
│ Row │ a           │ b        │ c           │
│     │ Float64     │ Float64  │ Float64     │
├─────┼─────────────┼──────────┼─────────────┤
│ 1   │ 0.000696453 │ 0.843809 │ 0.00231181  │
│ 2   │ 0.0012452   │ 0.106612 │ 0.000292088 │
│ 3   │ 0.00177015  │ 0.286037 │ 0.000783664 │
3

The latter is what I was trying to do, but looks like you managed to do it. Maybe it has something to do with my versions?
Julia v1.0.3 and DataFramesMeta v0.6?

4

I am on Julia v1.2.0 and DataFramesMeta v0.5.0.
Does the example I posted not work with your version?

I couldn’t try your example, since I don’t have dat. But note that in my example the dataframe df is the first argument of the marcro @transform.