[R] stacking the data elements in the list

[Im, Kelly]

Hello, 

I have a (rather simple) data manipulation question.. I have a list with
many datasets within, each dataset has observations in a format which
looks like

id x1 x2 x3 x4 x5 x6 y1 y2 y3 y4 y5 y6

how can I stack them so that it'll be 

id x1 x2 x3 x4 x5 x6
id y1 y2 y3 y4 y5 y6

for each patient,

I would very much appreciate your help,

thanks so much

kelly

-------------------------------------------------------------
KyungAh (Kelly)  Im   
Epidemiology Data Center
Graduate School of Public Health
Department of Epidemiology
University of Pittsburgh
PA 15261
PHONE:(412) 624- 4612 FAX: (412) 624- 3775
Email: Im at edc.pitt.edu
http://www.edc.gsph.pitt.edu