Aggregate data in one column based on values in another column

Question

I know there is an easy way to do this...but, I can\'t figure it out.

I have a dataframe in my R script that looks something like this:

A      B    C
1.2         


        

Answer 1

In dplyr:

library(tidyverse)
A <- c(1.2, 2.3, 2.3, 1.2, 3.4, 1.2)
B <- c(4, 4, 6, 3, 2, 5)
C <- c(8, 9, 0, 3, 1, 1)

df <- data_frame(A, B, C)

df %>%
    group_by(A) %>% 
    summarise(num = n(),
              totalB = sum(B))