How to generate many DataFrames with a loop using Julia

Question

I was wondering what was the most efective way of generating many DataFrames at once while on a loop.

I can't figure out how, but the output should be something like this:

df_1 = 1×3 DataFrame
│ Row │ var1         │
│     │ String       │
├─────┼──────────────┼
│ 1   │ b            │
│ 2   │ a            │
│ 3   │ c            │

df_2 = 1×3 DataFrame
│ Row │ var1         │
│     │ String       │
├─────┼──────────────┼
│ 1   │ h            │
│ 2   │ j            │
│ 3   │ k            │

etc etc

So, the name of the DataFrame should determined by the iteration of the loop (df_1, df_2).

Any help is welcome! Thank in advance.

Answer 1

I would recommend you to use e.g. a comprehension instead like this:

julia> df = [DataFrame(var1=rand(3)) for i in 1:3]
3-element Vector{DataFrame}:
 3×1 DataFrame
 Row ? var1
     ? Float64
????????????????
   1 ? 0.402916
   2 ? 0.562662
   3 ? 0.256056
 3×1 DataFrame
 Row ? var1
     ? Float64
????????????????
   1 ? 0.978262
   2 ? 0.898357
   3 ? 0.71393
 3×1 DataFrame
 Row ? var1
     ? Float64
????????????????
   1 ? 0.634487
   2 ? 0.813718
   3 ? 0.113087

Then you can select the data frame you want using indexing, e.g.:

julia> df[1]
3×1 DataFrame
 Row ? var1
     ? Float64
????????????????
   1 ? 0.402916
   2 ? 0.562662
   3 ? 0.256056

julia> df[2]
3×1 DataFrame
 Row ? var1
     ? Float64
????????????????
   1 ? 0.978262
   2 ? 0.898357
   3 ? 0.71393

julia> df[3]
3×1 DataFrame
 Row ? var1
     ? Float64
????????????????
   1 ? 0.634487
   2 ? 0.813718
   3 ? 0.113087

Defining variables with dynamic naming the way you asked for can be done but I would not recommend it as it can easily lead to bugs in your code.