turn some variables in `data.frame` into `factor` keeping the data.frame structure R

Question

I'm trying to turn some of the variables in my data.frame into factor while preserving the data.frame structure. I follow the suggestions HERE but I don't get my desired output, any fix?

d <- data.frame(a = c(1,2, 3, 5), b = c(2,3, 4, 2), e = c(3,4,5,1), f = rep(c("long", "short"), 2))
factor.name <- names(d)[-4]

d[] <- lapply(seq_along(factor.name), function(i) as.factor(d[factor.name[i]]))

you are trying to convert columns a,b and e into factors? – StupidWolf Oct 31 '19 at 17:25 — StupidWolf, Oct 31 '19 at 17:25
for(i in factor.name ){d[,i] = factor(d[,i])} – StupidWolf Oct 31 '19 at 17:27 — StupidWolf, Oct 31 '19 at 17:27
note, the last column f is a factor by default – StupidWolf Oct 31 '19 at 17:27 — StupidWolf, Oct 31 '19 at 17:27

score 2 · Accepted Answer · answered Oct 31 '19 at 17:27

2

Subset the data with 'factor.name', pass that in lapply and update the columns

d[factor.name] <- lapply(d[factor.name], factor)

answered Oct 31 '19 at 17:27

akrun

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1

Code could be cleaned up by eliminating the creation of `factor.name` with `d[,1:3] <- lapply(d[,1:3], factor)`. – LouisMP Oct 31 '19 at 17:53
1

@LouisPenrod I guess the OP's `factor.name` vector would be passed on from another function or so – akrun Oct 31 '19 at 17:55

score 1 · Answer 2 · answered Oct 31 '19 at 17:28

1

library(dplyr)
d <-
  d %>% 
  mutate_at(vars(a, b, e), as.factor)

answered Oct 31 '19 at 17:28

Iaroslav Domin

2,698
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19

turn some variables in `data.frame` into `factor` keeping the data.frame structure R

2 Answers2