Using dplyr to group_by and conditionally mutate a dataframe by group
问题 I'd like to use dplyr functions to group_by and conditionally mutate a df. Given this sample data: A B C D 1 1 1 0.25 1 1 2 0 1 2 1 0.5 1 2 2 0 1 3 1 0.75 1 3 2 0.25 2 1 1 0 2 1 2 0.5 2 2 1 0 2 2 2 0 2 3 1 0 2 3 2 0 3 1 1 0.5 3 1 2 0 3 2 1 0.25 3 2 2 1 3 3 1 0 3 3 2 0.75 I want to use new column E to categorize A by whether B == 1, C == 2, and D > 0. For each unique value of A for which all of these conditions hold true, then E = 1, else E = 0. So, the output should look like this: A B C D E