[R] Warning: matrix by vector division

[Alexey Shipunov]

Dear list,

I just made a very simple mistake, but it was hard to spot. And I
think that I should warn other people, because it is probably so
simple to make...

=== R code  ===

# Let us create a matrix:
(a <- cbind(c(0,1,1), rep(1,3)))

#      [,1] [,2]
# [1,]    0    1
# [2,]    1    1
# [3,]    1    1

# That is a MISTAKE:
a/colSums(a)

#           [,1]      [,2]
# [1,] 0.0000000 0.3333333
# [2,] 0.3333333 0.5000000
# [3,] 0.5000000 0.3333333
# I just wonder if some R warning should be issued here?

# That is what I actually needed (column-wise frequencies):
t(t(a)/colSums(a))

#      [,1]      [,2]
# [1,]  0.0 0.3333333
# [2,]  0.5 0.3333333
# [3,]  0.5 0.3333333

=== end of R code ===

With best wishes and regards,
Alexey Shipunov