[R] Mapping from one vector to another
Gang Chen
gangchen6 at gmail.com
Thu Jul 17 17:00:21 CEST 2014
Suppose I have the following dataframe:
L4 <- LETTERS[1:4]
fac <- sample(L4, 10, replace = TRUE)
(d <- data.frame(x = 1, y = 1:10, fac = fac))
x y fac
1 1 1 B
2 1 2 B
3 1 3 D
4 1 4 A
5 1 5 C
6 1 6 D
7 1 7 C
8 1 8 B
9 1 9 B
10 1 10 B
I'd like to add another column 'var' that is defined based on the
following mapping of column 'fac':
A -> 8
B -> 11
C -> 3
D -> 2
How can I achieve this in an elegant way (with a generic approach for
any length)?
Thanks,
Gang
More information about the R-help
mailing list