Change values in multiple columns of a dataframe using a lookup table

Question

I am trying to change the value of a number of columns at once using a lookup table. They all use the same lookup table. I know how to do this for just one column -- I\'d ju

Answer 1

Using dplyr

f <- function(x)setNames(lookup$letter, lookup$number)[x] 
library(dplyr)
example %>% 
  mutate_each(funs(f))
#  a b c
#1 A E A
#2 B D D
#3 C C C
#4 D B B
#5 E A E

Or with data.table

library(data.table)
setDT(example)[, lapply(.SD, f), ]
#   a b c
#1: A E A
#2: B D D
#3: C C C
#4: D B B
#5: E A E