Count By Subgroup

Asked Dec 17 '18 at 17:48

Active Dec 17 '18 at 17:48

Viewed 45 times

I have a dataframe like below:

      Col1   Col2    Col3   Col4
2018-01-12      A       B      2
2018-01-13      A       B      3
2018-01-14      A       C      5
2018-01-15      B       C      7
2018-01-16      B       D      8

How do I count the number of occurrences for combination of Col2 and Col3?

Final Expected Output:

      Col1   Col2    Col3   Col4   Count
2018-01-12      A       B      2       2
2018-01-13      A       B      3       2
2018-01-14      A       C      5       1
2018-01-15      B       C      7       1
2018-01-16      B       D      8       1

asked Dec 17 '18 at 17:48

nak5120

4,089
4
35
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5

`library(dplyr); dat %>% group_by(Col2, Col3) %>% mutate(Count=n())`, where `dat` is your data frame. – eipi10 Dec 17 '18 at 18:00
1

thanks, appreciate the help – nak5120 Dec 17 '18 at 18:02
4

If you don't care about the name, there is a simple one-liner: `add_count(df, Col2, Col3)` – arg0naut91 Dec 17 '18 at 18:15

Count By Subgroup

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