Lookup values in a vectorized way

Question

I keep reading about the importance of vectorized functionality so hopefully someone can help me out here.

Say I have a data frame with two columns: name

Answer 1

See ?merge which will perform a database link merge or join.

Here is an example:

set.seed(2)
d1 <- data.frame(ID = 1:5, Name = c("Bill","Bob","Jessica","Jennifer","Robyn"))
d2 <- data.frame(Name = c("Bill", "Gavin", "Bob", "Joris", "Jessica", "Andrie", 
                          "Jennifer","Joshua","Robyn","Iterator"),
                 Birthplace = sample(c("London","New York",
                                       "San Francisco", "Berlin",
                                       "Tokyo", "Paris"), 10, rep = TRUE))

which gives:

> d1
  ID     Name
1  1     Bill
2  2      Bob
3  3  Jessica
4  4 Jennifer
5  5    Robyn
> d2
       Name    Birthplace
1      Bill      New York
2     Gavin         Tokyo
3       Bob        Berlin
4     Joris      New York
5   Jessica         Paris
6    Andrie         Paris
7  Jennifer        London
8    Joshua         Paris
9     Robyn San Francisco
10 Iterator        Berlin

Then we use merge() to do the join:

> merge(d1, d2)
      Name ID    Birthplace
1     Bill  1      New York
2      Bob  2        Berlin
3 Jennifer  4        London
4  Jessica  3         Paris
5    Robyn  5 San Francisco