Solidifying a melted data frame?

Question

Assuming I have a melted data.frame that looks like this:

  variable       value
1         A -0.19933093
2         A -1.19043346
3         A -1.         


        

Answer 1

Alright, begin with a data frame in wide form, containing an id. melt() it to give the long form, then dcast() it to get back to the original data frame.

library(reshape2)
df = read.table(text = "id   A   B
1  1 -0.19933093 -0.10074686
2  2 -1.19043346  0.72451483
3  3 -1.32248172 -0.40914044
4  4 -1.98644507  0.02913376
5  5 -0.07930953  0.16062491", sep = "", header = TRUE)

df

df.melt = melt(df, "id")
df.melt

df.original = dcast(df.melt, id~variable)

df.original