CODEWITHSUNDEEP
rfindreplaceall
mik
mik

Reputation: 356

R - How to replace a set of values with another set of values

I have this problem which I can solve manually but I feel there must be an easier answer. I want to replace 2 with A, 22 with B, 4 with C, ... I have all the values I want to replace in an array and another [A,B,C,D,...]. Is there an easy way to perform this replacement? Thanks, Miguel

Upvotes: 1

Views: 1187

Answers (2)

Ven Yao
Ven Yao

Reputation: 3710

You can use named vectors.

x <- sample(1:10, 8)
x
# [1]  4  9  6 10  8  3  7  5
y <- c("A", "B", "C")
names(y) <- 1:3
x[x%in%names(y)] <- y[x[x%in%names(y)]]
x
# [1] "4"  "9"  "6"  "10" "8"  "C"  "7"  "5"

Upvotes: 4

black_sheep07
black_sheep07

Reputation: 2368

Use data.table

DT[column1 == "2", column1 := "A"]

If you want to do a group of them at a time, then use setkey from data.table and merge the dataset with the reference dataset.

setkeyv(DT, 'column1')
setkeyv(referenceSet, 'oldVars')

merge(DT, referenceSet, all.x = TRUE)

Upvotes: 2

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