Transforming data.frame in R

Question

I have the following data frame:

foo <- data.frame( abs( cbind(rnorm(3),rnorm(3, mean=.8),rnorm(3, mean=.9),rnorm(3, mean=1))))
colnames(foo) <- c(\"w\",\"         


        

Answer 1

reshape2:::melt() is particularly well suited to this transformation:

library(reshape2)

foo <- cbind(ID=rownames(foo),  foo)
melt(foo)
# Using ID as id variables
#    ID variable     value
# 1   n        w 1.7337416
# 2   q        w 0.5890877
# 3   r        w 0.2245508
# 4   n        x 0.5237346
# 5   q        x 0.9320455
# 6   r        x 0.8156573
# 7   n        y 1.9287306
# 8   q        y 1.1604229
# 9   r        y 1.7631215
# 10  n        z 0.3591350
# 11  q        z 0.9740170
# 12  r        z 0.5621968