@based_on not working? about dataframesmeta.jl

[davidagold]

@bramtayl Have you made sure that you're using the DataFramesMeta package as well as the DataFrames package? @based_on lives in the former. Perhaps a little confusing. You can add the former package by callingPkg.add("DataFramesMeta")`.

[bramtayl]

Yes. I checked the source for DataFramesMeta.@based_on, below.

macro based_on(x, args...)
  esc(:( DataFrames.based_on($x, _DF -> DataFramesMeta.@with(_DF, DataFrames.DataFrame($(args...)))) ))
end

However, it looks like DataFrames.based_on has been depreciated as of 0.5.2:

Removes expression-based indexing, including with, within!, based_on, etc.

[davidagold]

Ah, I totally misunderstood your question! I apologize. Are you looking for a way to produce something like:

3x2 DataFrame
| Row | Species      | mean_petal_length |
|-----|--------------|-------------------|
| 1   | "setosa"     | 1.462             |
| 2   | "versicolor" | 4.26              |
| 3   | "virginica"  | 5.552             |

?

[bramtayl]

Yes, and since I've written my post I've realized this can by done with @by.

[davidagold]

Indeed. Glad to hear. (Also, it's good to wrap macro names in ` s so as not to tag users with the same username as the macro name.)