Creating a new column of character values based on numeric value condition in R?

Question

How do I create a new column of character values based on numeric value that are to be assigned the following names: 0 = user, 1 = admin, 2 = sponsor

dat1 one two three 1 Bob 0 2 Mary 0 3 restaurant 2 4 company 1

so based on those names, how do I get to this:

dat1 one two three 1 Bob 0 user 2 Mary 0 user 3 restaurant 2 sponsor 4 company 1 admin dat1 <- data.frame(one=c("Bob", "Mary", "restaurant", "company"), two=c("0","0", "2", "1"))

And yes I know how simply create them via:

dat1 <- data.frame(one=c("Bob", "Mary", "restaurant", "company"), two=c("0","0", "2", "1"), three=c("user", "user", "sponsor", "admin"))

But what's the function that would preform the task? So under column three, based on the corresponding row under column two, I want 0 = user, 1 = admin, 2 = sponsor.

Rich Scriven · Accepted Answer · 2015-11-22 03:22:36Z

In your example, the two column is a factor. The integer representations of dat1$two as a factor are 1 for 0, 2 for 1, and 3 for 2. So if we use it as an index vector on a character vector of what we want to to get, we can expand the vector accordingly.

dat1$three <- c("user", "admin", "sponsor")[dat1$two] dat1 # one two three # 1 Bob 0 user # 2 Mary 0 user # 3 restaurant 2 sponsor # 4 company 1 admin

If you don't already have a factor in the two column, you can make it into one with the following.

dat1$three <- c("user", "admin", "sponsor")[as.factor(dat1$two)]

These both create a new character column.

Update: As Frank mentions, the more idiomatic method would be to simply factor the two column and apply different labels.

dat1$three <- factor(dat1$two, labels = c("user", "admin", "sponsor"))

This creates a new factor column.

Collectives™ on Stack Overflow

Creating a new column of character values based on numeric value condition in R?

1 Answer 1

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Linked

Related