rename and mutate character values

[Lilip]

Hey, I´m trying to rename some string values ( that contain specific parts) to another strings. Tried in the starwars tibble (dyplr). I want to rename many of them differently.

.*Na is for Naboo
.*oo is for Tatooine

df_test1 <- starwars  %>% 
  mutate(new_homeworld = gsub ("[.*Na.* | .*oo.*]", "A" ,homeworld)
df_test1

It did not work

Also tried

df_test2 <- starwars  %>% 
  mutate(new_homeworld = case_when(homeworld == ".*Na.*" ~ "A",
                                      homeworld == ".*oo.*" ~ "B",
                                      TRUE ~ "C")) 

Just get " C" for all values

Any thoughts on that?

[nirgrahamuk]

I added a letter to each matching fragment, so it didnt also tag homeworlds that arent Naboo or Tatooine

df_test1 <- starwars %>% select(name,homeworld) %>%
  mutate(is_naboo_or_tatooine = str_detect(homeworld,pattern="Nab|too"),
         new_homeworld = case_when(is_naboo_or_tatooine ~ "A",
                                   TRUE ~ homeworld))
         
         df_test1

[Lilip]

@nirgrahamuk

df_test1 <- starwars %>% select(name,homeworld) %>%
  mutate(is_naboo_or_tatooine = str_detect(homeworld,pattern="Nab|too"),
         new_homeworld = case_when(is_naboo_or_tatooine ~ "A",
                                   TRUE ~ homeworld))

Thanks. But it did not work for me.

Just tried, but it also did not work usin ".*"

df_test3 <- starwars %>%
mutate(new_homeworld = gsub (".Nab.", "A" ,homeworld),
(new_homeworld = gsub (".too.", "B" ,homeworld),
new_homeworld = gsub (".Ste.", "C" ,homeworld)))

df_test3

[nirgrahamuk]

@Lilip

Thanks. But it did not work for me.

I don't what you mean ?
did you get an error ? what error did you get ?
did it run without error, but give an improper result ? how so ?

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[Lilip]

It wasn´t mutating in the whole tibble. But I figured, it was the select function. I just removed it.

Tried two diffrent ways and they worked!

df_test4 <- starwars %>% 
    mutate(is_naboo_or_tatooine = str_detect(homeworld,".*Nab.*|.*too.*"),
           is_stewjon_or_eriadu = str_detect(homeworld,".*Ste.*|.*Eri.*"),
           new_homeworld = case_when(is_naboo_or_tatooine ~ "A",
                                     is_stewjon_or_eriadu ~ "B",
                                     TRUE ~ homeworld))

  df_test5 <- starwars %>% 
    mutate(new_homeworld = case_when(str_detect(homeworld,".*Nab.*|.*too.*") ~ "A",
                                     str_detect(homeworld,".*Ste.*|.*Eri.*") ~ "B",
                                     TRUE ~ homeworld))

What do you think about them? You helped me a lot with the str_detect. Thanks

[nirgrahamuk]

I think the additional punctuation marks .* etc are superflous.

df_test5 <- starwars %>% 
  mutate(new_homeworld = case_when(str_detect(homeworld,".*Nab.*|.*too.*") ~ "A",
                                   str_detect(homeworld,".*Ste.*|.*Eri.*") ~ "B",
                                   TRUE ~ homeworld))
df_test6 <- starwars %>% 
  mutate(new_homeworld = case_when(str_detect(homeworld,"Nab|too") ~ "A",
                                   str_detect(homeworld,"Ste|Eri") ~ "B",
                                   TRUE ~ homeworld))

identical(df_test5$new_homeworld,
               df_test6$new_homeworld)

or at least for the starwars input