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

I would suggest using the dplyr package for this

See below:

require(dplyr)

data %>% 
  mutate(
    Category_factored=as.numeric(factor(Category,levels=c('PT','DI','GT','SY'),labels=1:4))
  ) %>% 
  group_by(Name,Course) %>% 
  filter(
    Category_factored == min(Category_factored)
  )

In case you are new to R, install dplyr using install.packages('dplyr')