Convert dictionary of dataframes into single dataframe

General Usage
1

I have a dictionary of dataframes that I want to combine into a single dataframe.

image

2

This didn’t work.

test2 = hcat(speed_steps)

image
image1099×547 64.8 KB

3

I think you probably want vcat rather than hcat.

reduce(vcat, values(speed_steps))
3 Likes
4

pdeffebach,

Yes, that worked. Thanks!

5

If you, or another reader stumbling across this topic, also want to add the keys to the DataFrame, you can iterate over the keys and values and add the keys as a column to the individual data frames. For example,

julia> A = DataFrame(TimeInterval = [1])
1×1 DataFrame
 Row │ TimeInterval
     │ Int64
─────┼──────────────
   1 │            1

julia> B = DataFrame(TimeInterval = [2])
1×1 DataFrame
 Row │ TimeInterval
     │ Int64
─────┼──────────────
   1 │            2

julia> speeds = Dict(0.3 => A, 0.9 => B)
Dict{Float64, DataFrame} with 2 entries:
  0.3 => 1×1 DataFrame…
  0.9 => 1×1 DataFrame…

julia> for (speed, df) in zip(keys(speeds), values(speeds))
       df[!, :speed] .= speed
       end;

julia> vcat(values(speeds)...)
2×2 DataFrame
 Row │ TimeInterval  speed
     │ Int64         Float64
─────┼───────────────────────
   1 │            1      0.3
   2 │            2      0.9
1 Like
6

rikh,

Thanks. I probably will eventually need to do that. I’m making the jump from Python. There’s been a slight learning curve for me.

1 Like