使用查找向量替换变量中的字符串

Question

我有一个带有字符变量的数据帧df以及fromvec和tovec.

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

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

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

在fromvec中使用字符串,在df中检查它们,然后用tovec中的相应字符串替换它们,以便df中的"A"替换为"X","B"替换为"Y",依此类推以获得desired_df.

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

我试过跟随,但没有得到预期的结果!

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))

即这个

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

请帮我拿到desired_df.

Answer 1

你可以使用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    

或者我们可以使用 recode

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

如果你真的想用,str_replace你可以这样做:

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