Group values with identical ID into columns without summerizing them in R

Question

I have a dataframe that looks like this, but with a lot more Proteins

Protein      z
  Irak4  -2.46
  Irak4  -0.13
    Itk  -0.49
    Itk   4.22
    Itk  -0.51
          


        

Answer 1

library(data.table)

dcast(setDT(df),rowid(Protein)~Protein,value.var='z')

   Protein Irak4   Itk  Ras
1:       1 -2.46 -0.49 1.53
2:       2 -0.13  4.22   NA
3:       3    NA -0.51   NA

in base R you can do:

data.frame(sapply(a<-unstack(df,z~Protein),`length<-`,max(lengths(a))))
  Irak4   Itk  Ras
1 -2.46 -0.49 1.53
2 -0.13  4.22   NA
3    NA -0.51   NA

Or using reshape:

reshape(transform(df,gr=ave(z,Protein,FUN=seq_along)),v.names = 'z',timevar = 'Protein',idvar = 'gr',dir='wide') 
  gr z.Irak4 z.Itk z.Ras
1  1   -2.46 -0.49  1.53
2  2   -0.13  4.22    NA
5  3      NA -0.51    NA