[R] split the data.frame

[YIHSU CHEN]

Dear R folks:

I wonder anyone has a elegent way of doing what I need to do.

I have a data frame called with four columns: V1, V2, A1 and A2:

V1  V2  A1   A2
A    B    1.2  2.0
A    D    1.2  4.0
A    C    2.4  2.2

What I need to do is to convert it into the following data frame with a new column x, where x is just the stacked up of A1 and A2 placed with respective V1 and V2 in the first two columns:  

V1  V2   x 
A    B    1.2
A    B    2.0
A    D    1.2
A    D    4.0
A    C    2.4
A    C    2.2

I wonder whether there is an efficient way to do it since I have huge dataset. 

Thank you very much

Yihsu













 







Yihsu Chen
The Johns Hopkins University