Assign list name to dataframe list element

Question

I have a list of lists of dataframes:

library(dplyr)
library(magrittr)

a <- list(first = data.frame(x=runif(1), y=runif(1)),
          second = data.frame(x=runif(5), y=runif(5)))
b <- list(first = data.frame(x=runif(1), y=runif(1)),
          second = data.frame(x=runif(5), y=runif(5)))
a <- a %>% set_names(1:length(a))
b <- b %>% set_names(1:length(b))
c <- list(a, b)
c <- c %>% set_names(1:length(c))

I want to assign the two levels of list names as new columns to the dataframe, and then bind them into one dataframe. The desired output is something like:

  x    y   name1   name2
.23  .43       1       1
.23  .43       1       2
.23  .43       2       1
.23  .43       2       2

Where the values of x and y are not the point. I am struggling with this as lapply does not access the name of the element of the list.

Thanks.

The code produced errors on my end after the lines containing %>% . (I have dplyr loaded). I presume you use a package like magrittr? may be good to know for those who want to replicate the question. — Ricky
– Ricky, Commented Jan 19, 2015 at 7:14

akrun · Accepted Answer · 2015-01-19 08:23:51Z

2

May be this helps:

library(reshape2)
library(tidyr)
library(dplyr)
res <- melt(c) %>%
             group_by(variable) %>% 
             mutate(indx=row_number()) %>%
             spread(variable, value) %>% 
             ungroup() %>% 
             select(-indx)

answered Jan 19, 2015 at 8:23

akrun

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