R: Remove duplicates from a dataframe based on categories in a column

Question

Here is my example data set:

      Name Course Cateory
 1: Jason     ML      PT
 2: Jason     ML      DI
 3: Jason     ML      GT
 4: Jason     ML      SY
 5: Ja         


        

Answer 1

You'll need to create an index to represent the order of category. Then sort based on the priority of your categories and dedup by Name and Course.

library(tidyverse)

#create index to sort by
index.df <- data.frame("Cateory" = c('PT',"DI","GT","SY"), "Index" = c(1,2,3,4))

#join to orig dataset
data <- left_join(data, index.df, by = "Cateory")

#sort by index, dedup with Name and Course
data %>% arrange(Index) %>% group_by(Name,Course) %>% 
distinct(Name,Course, .keep_all = TRUE) %>% select(-Index)