Counting rows that match result of calculation in R-CodePudding

I have a line of code that calculates the maximum value for a number of products

data2019 %>%
  group_by(PRODUCT) %>%
  summarise(max_amt = max(AMOUNT))

I want to then count the number of rows where AMOUNT == max_amt for that particular product, but if I try to wrap it in a count or sum function it gives me the max value for the whole set, and the total number of rows for each product, which isn't very helpful, especially as the values vary considerably. How can I get it to produce the answer for each specific product?

CodePudding user response：

You can do a count on condition by writing your summarize like sum(CONDITION). Like so:

data2019 %>%
  group_by(PRODUCT) %>%
  summarize(max_count = sum(AMOUNT == max(AMOUNT)))