R: How to keep names while unnesting doubled nested tibble? - r

Question

at the moment I'm trying to figure out how to keep the names of an inner and other list nested within a tibble while unnesting.
The .id parameter of the unnest function is the closest I found, but it starts to number the values instead of using the given names.
here is a MWE with my idea of the final tibble:
library(dplyr)
library(tidyr)
df.1 <- tibble(
x = list("Foo","Bar"),
y = list(
list(a = list(aa = 1, ab = 2), b = list(ba = 6, bb = 22)),
list(c = list(ca = 561, cb = 35), d = list(da = 346, db = 17))
)
)
df.2 <- unnest(df.1, .id = "name.outher")
df.3 <- unnest(df.2, .id = "name.inner")
# How do I get from this:
#
#-----------------------------------------------------------------------
# x | y |
#-----+----------------------------------------------------------------+
# Foo | list(a = list(aa = 1, ab = 2), b = list(ba = 6, bb = 22)) |
#-----+----------------------------------------------------------------+
# Bar | list(c = list(ca = 561, cb = 35), d = list(da = 346, db = 17)) |
#-----------------------------------------------------------------------
#
# to this:
#
#---------------------------------------
# x | name.outher | y | name.inner |
#-----+-------------+-----+------------+
# Foo | a | 1 | aa |
#-----+-------------+-----+------------+
# Foo | a | 2 | ab |
#-----+-------------+-----+------------+
# Foo | b | 6 | ba |
#-----+-------------+-----+------------+
# Foo | b | 22 | bb |
#-----+-------------+-----+------------+
# Bar | c | 561 | ca |
#-----+-------------+-----+------------+
# Bar | c | 35 | cb |
#-----+-------------+-----+------------+
# Bar | d | 346 | da |
#-----+-------------+-----+------------+
# Bar | d | 17 | db |
#-------------------------------------
#
# instead of this:
#
#---------------------------------------
# x | name.outher | y | name.inner |
#-----+-------------+-----+------------+
# Foo | 1 | 1 | 1 |
#-----+-------------+-----+------------+
# Foo | 1 | 2 | 1 |
#-----+-------------+-----+------------+
# Foo | 1 | 6 | 2 |
#-----+-------------+-----+------------+
# Foo | 1 | 22 | 2 |
#-----+-------------+-----+------------+
# Bar | 2 | 561 | 3 |
#-----+-------------+-----+------------+
# Bar | 2 | 35 | 3 |
#-----+-------------+-----+------------+
# Bar | 2 | 346 | 4 |
#-----+-------------+-----+------------+
# Bar | 2 | 17 | 4 |
#---------------------------------------
Do you have any idea how i can preserve the names while unnesting this data structure?

Answer 1

We can melt
library(reshape2)
library(dplyr)
df.1 %>%
.$y %>%
melt %>%
select(x = L1, name.outher = L2, y = value, name.inner = L3)
# x name.outher y name.inner
#1 1 a 1 aa
#2 1 a 2 ab
#3 1 b 6 ba
#4 1 b 22 bb
#5 2 c 561 ca
#6 2 c 35 cb
#7 2 d 346 da
#8 2 d 17 db
Or use map and as_tibble
library(tidyverse)
df.1 %>%
pull(y) %>%
map_df(~ as_tibble(.x) %>%
map_df(~as_tibble(.x) %>%
gather(name.inner, y), .id = 'name.outer'),
.id = 'x')
# A tibble: 8 x 4
# x name.outer name.inner y
# <chr> <chr> <chr> <dbl>
#1 1 a aa 1
#2 1 a ab 2
#3 1 b ba 6
#4 1 b bb 22
#5 2 c ca 561
#6 2 c cb 35
#7 2 d da 346
#8 2 d db 17