Hi,
In DataFrames, it is easy to apply a function by columns using the colwise()
function. But I find very difficult and inefficient to apply a function by
rows.
For example :
julia> df = DataFrame(a=1:5, b=7:11, c=10:14)
5x3 DataFrames.DataFrame
| Row | a | b | c |
|-----|---|----|----|
| 1 | 1 | 7 | 10 |
| 2 | 2 | 8 | 11 |
| 3 | 3 | 9 | 12 |
| 4 | 4 | 10 | 13 |
| 5 | 5 | 11 | 14 |
julia> colwise(mean,df)
3-element Array{Any,1}:
[3.0]
[9.0]
[12.0]
julia> colwise(mean,df[1,1:2])
2-element Array{Any,1}:
[1.0]
[7.0]
To calculate the mean of a row (or a subset), the only way I found is this :
julia> mean(convert(Array,df[1,1:3]))
6.0
I think this is inefficient and probably very slow. I there a better way to
apply a function by rows ?
Thanks !
