How to find the average rating for each category within each group?-CodePudding

I have a dataframe that contains ratings for games and they are divided into categories and whether or not the game is a solo game or not.

category <- c("Party","Adventure","Puzzle","Party","Adventure","Puzzle","Party","Adventure","Puzzle","Party","Adventure","Puzzle","Party","Adventure","Puzzle","Party","Adventure","Puzzle")
solo <- c("solo","solo","solo","double","double","double","solo","solo","solo","double","double","double","solo","solo","solo","double","double","double")
rating <- c(8,7,6,5,3,3,2,1,10,3,4,5,6,3,2,1,3,1) 
df <- as.data.frame(rating)
df$solo <- solo
df$category <- category

My question is, how do I get the average rating for each category that belongs to each grouping (solo/double)? Solo Party and Double Party should have different avg ratings for example.

CodePudding user response：

After grouping by 'category' and 'solo', get the mean

library(dplyr)
df <- df %>% 
  group_by(category, solo) %>% 
  mutate(avg = mean(rating, na.rm = TRUE)) %>%
  ungroup

-output

df
# A tibble: 18 × 4
   rating solo   category    avg
    <dbl> <chr>  <chr>     <dbl>
 1      8 solo   Party      5.33
 2      7 solo   Adventure  3.67
 3      6 solo   Puzzle     6   
 4      5 double Party      3   
 5      3 double Adventure  3.33
 6      3 double Puzzle     3   
 7      2 solo   Party      5.33
 8      1 solo   Adventure  3.67
 9     10 solo   Puzzle     6   
10      3 double Party      3   
11      4 double Adventure  3.33
12      5 double Puzzle     3   
13      6 solo   Party      5.33
14      3 solo   Adventure  3.67
15      2 solo   Puzzle     6   
16      1 double Party      3   
17      3 double Adventure  3.33
18      1 double Puzzle     3