everyone!
Here’s the problem , I have this dataset and I need to add a column with the frequency of each pet, I don’t want a new dataframe with the statistics. See, dog and cat appears 6 time each, I need a column with value of 6 beside each dog and cat. Then I’ll be able to make relational studies, which is why creating a new dataframe with summary is not an option
id answer
<chr> <chr>
1 1 cat
2 1 dog
3 2 bird
4 3 cat
5 3 dog
6 3 fish
7 4 dog
8 5 turtle
9 6 cat
10 7 cat
11 7 fish
12 7 dog
13 7 cat
14 8 dog
15 8 cat
16 9 bird
17 9 dog
by the end, it should look like this:
>Solution :
Using data.table you can group by frequency with .N
library(data.table)
your_table = as.data.table(your_table)
your_table[,freq := .N, by = answer]
# id answer freq
# 1: 1 cat 6
# 2: 1 dog 6
# 3: 2 bird 2
# 4: 3 cat 6
# 5: 3 dog 6
# 6: 3 fish 2
# 7: 4 dog 6
# 8: 5 turtle 1
# 9: 6 cat 6
# 10: 7 cat 6
# 11: 7 fish 2
# 12: 7 dog 6
# 13: 7 cat 6
# 14: 8 dog 6
# 15: 8 cat 6
# 16: 9 bird 2
# 17: 9 dog 6