I want to make a contingency table with observations and their predictions based on a neural network. Since I want positives to be on the diagonal, I would like my table to be squared, regardless if there are rows with just 0's. That is, I would like to have
b
a a b c d e f g
a 1 0 1 0 2 1 0
b 0 0 0 0 0 0 0
c 0 0 0 0 0 0 0
d 2 3 1 2 2 3 2
e 1 2 1 1 0 1 3
f 0 0 0 0 0 0 0
g 4 2 1 0 3 1 0
Instead of:
> set.seed(1)
> b<-sample(letters[1:7],40,rep=TRUE)
> a<-sample(letters[1:4],40,rep=TRUE)
>
> table(a,b)
b
a a b c d e f g
a 1 0 1 0 2 1 0
d 2 3 1 2 2 3 2
e 1 2 1 1 0 1 3
g 4 2 1 0 3 1 0
How can I do this?
Convert a and b to factor with levels as union of both :
tmp <- sort(union(a, b))
table(factor(a, levels = tmp), factor(b, levels = tmp))
# a b c d e f g
# a 0 1 1 2 2 1 4
# b 2 1 1 1 2 3 2
# c 4 0 1 2 0 1 1
# d 0 1 1 1 3 1 1
# e 0 0 0 0 0 0 0
# f 0 0 0 0 0 0 0
# g 0 0 0 0 0 0 0