Replace strings in variable using lookup vector

Question

I have a dataframe df with a character variable and the fromvec and tovec.

df <- tibble(var = c("A", "B", "C", "a", "E", "D", "b"))

fromvec <- c("A", "B", "C")

tovec <- c("X", "Y", "Z")

Use strings in fromvec, check them in df and then replace them with the corresponding strings in tovec so that "A" in df gets replaced with "X", "B" with "Y" and so on to get the desired_df.

desired_df <- tibble(var = c("X", "Y", "Z", "X", "E", "D", "Y"))

I tried following, but not getting the desired result!

from_vec <- paste(fromvec, collapse="|") 
to_vec <- paste(tovec, collapse="|") 

undesired_df <- df %>% 
  mutate(var = str_replace(str_to_upper(var), from_vec, to_vec))

i.e. this

tibble(var = c("X|Y|Z", "X|Y|Z", "X|Y|Z", "X|Y|Z", "E", "D", "X|Y|Z"))

How can I get the desired_df?

Answer 1

You could use chartr :

df$var <- chartr(paste(fromvec,collapse=""),
                 paste(tovec,collapse=""),
                 toupper(df$var))
# # A tibble: 7 x 1
#   var  
#   <chr>
# 1 X    
# 2 Y    
# 3 Z    
# 4 X    
# 5 E    
# 6 D    
# 7 Y    

---

Or we can use recode

library(dplyr)
df$var <- recode(toupper(df$var), !!!setNames(tovec,fromvec))

---

If you really want to use str_replace you could do:

library(purrr)
library(stringr)
df$var <- reduce2(fromvec, tovec, str_replace, .init=toupper(df$var))

Answer 2

The correct way to do this with stringr is with str_replace_all:

mutate(df,str_replace_all(str_to_upper(var),setNames(tovec, fromvec)))

(thanks, @Moody_Mudskipper!)