# NOT RUN {
test_df <- data.table(
a = 1:3,
b = 4:6,
c = c("a","a","b"),
d = c("a","a","b")
)
test_df %>%
summarize.(avg_a = mean(a),
max_b = max(b),
.by = c)
test_df %>%
summarize.(avg_a = mean(a),
.by = c(c, d))
# }
Run the code above in your browser using DataLab