Histogram

From: Mag. Ferri Leberl

Dear everybody!
I am analysing data from an enquette. The answers are either 
A or B. How can I 
draw a histogram without transforming the data from 
characters to numbers? If 
the data are saved in a list M, hist(M[,1]) returns:

Error in hist.default(M[, 1]) : `x' must be numeric
Execution halted

hist.factor <- function(x, ...) barplot(table(x), ...)
f <- factor(sample(c("A", "B"), 50, replace=TRUE))
hist(f)

Thank you in advance!