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anderwyang
anderwyang

Reputation: 2431

In R ,how to collapse character into new group

I R, I want to add new character group 'region_new ', it seems 'if else' not work. Any one can help ? thank

test_data <- data.frame(region=LETTERS)

test_data$region_new <- ''
if (test_data$region in c('a','b','c')){
   test_data$region_new <- 'Level_A'
} else if (test_data$region in c('d','x','z')) {
   test_data$region_new <- 'Level_B'
} else {
   test_data$region_new <- 'Level_Other'
}

Upvotes: 0

Views: 52

Answers (1)

Ronak Shah
Ronak Shah

Reputation: 388982

You need vectorized ifelse instead of if/else. Also use %in% instead of in.

You can also use case_when from dplyr -

library(dplyr)
test_data <- data.frame(region=LETTERS)

test_data %>%
  mutate(region_new = case_when(region %in% c('A','B','C') ~ 'Level_A', 
                                region %in% c('D','X','Z') ~ 'Level_B',
                                TRUE ~ 'Level_Other'))

Another option is to use fct_collapse from forcats.

test_data %>%
  mutate(region_new = forcats::fct_collapse(region, 
                                   Level_A = c('A','B','C'), 
                                   Level_B = c('D','X','Z'), 
                                   other_level = 'Level_Other'))

Upvotes: 1

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