How to convert a mixed-type Matrix to DataFrame in Julia recognising the column types

Question

One nice feature of DataFrames is that it can store columns with different types and it can \"auto-recognise\" them, e.g.:

using DataFrames, DataStructures

df1          


        

Answer 1

While I didn't find a complete solution, a partial one is to try to convert the individual columns ex-post:

"""
    convertDf!(df)

Try to convert each column of the converted df from Any to In64, Float64 or String (in that order).    
"""
function convertDf!(df)
    for c in names(df)
        try
          df[c] = convert(DataArrays.DataArray{Int64,1},df[c])
        catch
            try
              df[c] = convert(DataArrays.DataArray{Float64,1},df[c])
            catch
                try
                  df[c] = convert(DataArrays.DataArray{String,1},df[c])
                catch
                end
            end
        end
    end
end 

While surely incomplete, it is enough for my needs.