Reshape long to wide with multiple groupings

Question

My data looks like this:

  Smoker PtNo Day Hour FEV1 timename
1       0    1   1    0 3.26     d1h0
2       0    1   1    2 3.05     d1h2
3       0    1   1    4         


        

Answer 1

> dcast(df, PtNo + Smoker ~ timename, value.var="FEV1")
 PtNo Smoker   d1h0 d1h2 d1h4 d1h6 d2h0 d2h2 d2h4 d2h6 d3h0 d3h2
1   1      0   3.26 3.05 3.02 3.27 3.28 3.07 3.35 3.07 3.28 3.44

If you want the col names to be exactly as you have them, then you can just paste "FEV1" to timename before you dcast. dcast is from package reshape2.