Replacing strings with digits automatically

Question

I have a pretty huge data frame with a column in which some personal emails are repeated hundred times, such as (please see figure below):

is there a function/package which can handle this automatically?

Thanks!

Answer 1

Just try

x <- c("a","a","b","b","v","w") #your emails
numbers <- as.numeric(as.factor(x))

or

numbers <- match(x,unique(x))