How to replace multiple values in a string depending on a list of keys

问题

I have this data which I want to replace each value with a fixed value from another list

values
key1
key3;key4;key1
key2;key1

Here is the list that "translates" each key into something else (these are just examples so it is not enought to just change the word "key" to "code".

key    code
key1  code1
key2  code2
key3  code3
key4  code4

So the end product should look like this:

values
code1
code3;code4;code1
code2;code1

This is how I tried to solve it but got stuck:

values = tibble(id = 1:3, values = c("key1", "key3;key4;key1", "key2;key1"))
key_code = tibble(key = c("key1", "key2", "key3", "key4"), code = c("code1", "code2", "code3", "code4"))

values %>% 
  mutate(values = strsplit(values, ";")) %>% 
  unnest(values) %>% 
  left_join(key_code, by = c("values" = "key"))

This is what I get

# A tibble: 6 x 2
     id code 
  <int> <chr>
1     1 code1
2     2 code3
3     2 code4
4     2 code1
5     3 code2
6     3 code1

From here I want to get:

    id code 
  <int> <chr>
1     1 code1
2     2 code3;code4;code1
3     3 code2;code1

回答1:

We can use paste or str_c. Instead of strsplit, another option is separate_rows

library(dplyr)
library(tidyr)
library(stringr)
values %>% 
    separate_rows(values) %>% 
    left_join(key_code, by = c("values" = "key")) %>% 
    group_by(id) %>%
    summarise(code = str_c(code, collapse=";"))
# A tibble: 3 x 2
#     id code             
#  <int> <chr>            
#1     1 code1            
#2     2 code3;code4;code1
#3     3 code2;code1

Or an easier option is str_replace which can take a named vector or list and use that to replace the values in the string without even splitting or joining

values %>% 
  mutate(values = str_replace_all(values, set_names(key_code$code, key_code$key)))
# A tibble: 3 x 2
#     id values           
#  <int> <chr>            
#1     1 code1            
#2     2 code3;code4;code1
#3     3 code2;code1

来源：https://stackoverflow.com/questions/61447144/how-to-replace-multiple-values-in-a-string-depending-on-a-list-of-keys

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