Adding a column to a dataframe and conditionally filling based on another column within the same dataframe

New to Julia
1

I’m trying to write code to do the following, I’m completely new to Julia and coding in general so really struggling.
I have a data frame of columns and rows, I need to add a new column (EVID) to the df and conditionally fill based on the values in a different column (AMT). The conditional rule is “if AMT is missing then EVID is equal to 0. If AMT is not missing then EVID is equal to 1”

I think what I’m stumbling on is doing two things at once, i.e. inserting a new column (EVID) and then conditionally filling it based on the contents of a different column.

2

Here’s a solution with DataFramesMeta.jl

julia> using DataFramesMeta, DataFrames

julia> df = DataFrame(AMT = [1, 4, 3, missing, 3, 2])
6×1 DataFrame
 Row │ AMT     
     │ Int64?  
─────┼─────────
   1 │       1
   2 │       4
   3 │       3
   4 │ missing 
   5 │       3
   6 │       2

julia> @rtransform df :EVID = ismissing(:AMT) ? 0 : 1
6×2 DataFrame
 Row │ AMT      EVID  
     │ Int64?   Int64 
─────┼────────────────
   1 │       1      1
   2 │       4      1
   3 │       3      1
   4 │ missing      0
   5 │       3      1
   6 │       2      1
1 Like
3

Thank you.

4

TidierData.jl is another option that would look like this

julia> using TidierData

julia> df = DataFrame(AMT = [1, 4, 3, missing, 3, 2])
6×1 DataFrame
 Row │ AMT     
     │ Int64?  
─────┼─────────
   1 │       1
   2 │       4
   3 │       3
   4 │ missing 
   5 │       3
   6 │       2

julia> @mutate(df, EVID = if_else(ismissing(AMT), 0, 1))
6×2 DataFrame
 Row │ AMT      EVID  
     │ Int64?   Int64 
─────┼────────────────
   1 │       1      1
   2 │       4      1
   3 │       3      1
   4 │ missing      0
   5 │       3      1
   6 │       2      1
2 Likes
5

Or just broadcast ifelse.()

using DataFrames
df = DataFrame(AMT = [1, 4, 3, missing, 3, 2])
df.EVID = ifelse.(ismissing.(df.AMT), 0, 1)

6×2 DataFrame
 Row │ AMT      EVID  
     │ Int64?   Int64 
─────┼────────────────
   1 │       1      1
   2 │       4      1
   3 │       3      1
   4 │ missing      0
   5 │       3      1
   6 │       2      1
1 Like