in R: Two Way Match to Matrix

Question

If I have a data.frame

df <- data.frame(DEP=letters[1:5], ARR=letters[11:15], NO=1:5+5)

   DEP ARR  NO
1   a   k   6
2   b   l   7
3   c   m   8
4   d   n            


        

Answer 1

?xtabs:

xtabs(NO ~ ., data=df)
#   ARR
#DEP  k  l  m  n  o
#  a  6  0  0  0  0
#  b  0  7  0  0  0
#  c  0  0  8  0  0
#  d  0  0  0  9  0
#  e  0  0  0  0 10