Dictionary style replace multiple items

Question

I have a large data.frame of character data that I want to convert based on what is commonly called a dictionary in other languages.

Currently I am going about it li

Answer 1

Since it's been a few years since the last answer, and a new question came up tonight on this topic and a moderator closed it, I'll add it here. The poster has a large data frame containing 0, 1, and 2, and wants to change them to AA, AB, and BB respectively.

Use plyr:

> df <- data.frame(matrix(sample(c(NA, c("0","1","2")), 100, replace = TRUE), 10))
> df
     X1   X2   X3 X4   X5   X6   X7   X8   X9  X10
1     1    2   2    1    2    0    2    0    2
2     0    2    1  1    2    1    1    0    0    1
3     1    0    2  2    1    0     0    1 
4     1    2   2    2    2    1    1    0    1
... to 10th row

> df[] <- lapply(df, as.character)

Create a function over the data frame using revalue to replace multiple terms:

> library(plyr)
> apply(df, 2, function(x) {x <- revalue(x, c("0"="AA","1"="AB","2"="BB")); x})
      X1   X2   X3   X4   X5   X6   X7   X8   X9   X10 
 [1,] "AB" "BB" NA   "BB" "AB" "BB" "AA" "BB" "AA" "BB"
 [2,] "AA" "BB" "AB" "AB" "BB" "AB" "AB" "AA" "AA" "AB"
 [3,] "AB" "AA" "BB" "BB" "AB" "AA" NA   "AA" "AB" NA  
 [4,] "AB" "BB" NA   "BB" "BB" "BB" "AB" "AB" "AA" "AB"
... and so on