Duplication Rows by creating same columns in R

Question

I use below to create a list of AuthorId:

df.Author <- tibble::rowid_to_column(data.frame(df.Author,"AuthorId"))

However I want to make the dupilcation as a same id.

I want to change the AuthorId in dataframe. Like all Mazumdar's AuthorId is 3.

What should I do? The reason why I didn't delete the duplication is that there are other attribute in this table are not the same. Just names are duplicating, so I want them to have a same ID.

Answer 1

We may need match

nm1 <- with(df.Author, paste(LastName, FirstName))
df.Author$AuthorId <- match(nm1, unique(nm1))