Add a cumulative sum column to a data frame using dplyr

dplyr_cumsum_column.R

df %>% 
  group_by(id) %>% 
  mutate(cumsum = cumsum(value)) %>% 
  ungroup()

# from \url{http://stackoverflow.com/a/21818500/393354}

Does not workks

Fixed.

Does not work (Aug 6, 2020)

@westland It works for me. Try:

library(tidyverse)
data_df <- tibble(id = sample(letters[1:4], 15,
                   replace = TRUE),
       value = runif(15))

data_df %>% 
  group_by(id) %>% 
  mutate(cs = cumsum(value)) %>% 
  ungroup() %>% 
  arrange(id)