Number of observations in each group
Helper function that can be used to find counts by group.
Can be used inside summarize.(), mutate.(), & filter.()
n.()
test_df <- data.table(
x = 1:3,
y = 4:6,
z = c("a","a","b")
)
test_df %>%
summarize.(count = n.(), .by = z)
# The dplyr version `n()` also works
test_df %>%
summarize.(count = n(), .by = z)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.