How do you pivot data from a list of data frames in R?

Question

Let\'s say I have a list of data frames ldf:

df1 <- data.frame(date = c(1,2), value = c(4,5))
df2 <- data.frame(date = c(1,2), value = c(4,5))
ldf <- li         


        

Answer 1

Another option is to use unnest from "tidyr" in conjunction with the typical grouping and aggregation functions via "dplyr":

library(dplyr)
library(tidyr)

unnest(ldf) %>%
  group_by(date) %>%
  summarise(value = sum(value))
# Source: local data frame [2 x 2]
# 
#   date value
# 1    1     8
# 2    2    10