Column bind several list elements based on id variable

Question

Assuming the following list:

a <- data.frame(id = 1:3, x  = 1:3)
b <- data.frame(id = 3:1, y  = 4:6)
my_list <- list(a, b)

my_list
# [[1]]
#   id x
# 1  1 1
# 2  2 2
# 3  3 3

# [[2]]
#   id y
# 1  3 4
# 2  2 5
# 3  1 6

I now want to column bind the list elements into a data frame/tibble while matching the respective rows based on the id variable, i.e. the outcome should be:

# A tibble: 3 x 3
     id     x     y
  <int> <int> <int>
1     1     1     6
2     2     2     5
3     3     3     4

I know how I can do it with some pivoting, but I'm wondering if there's a smarter way of doing it and I hoped there was some binding function that simply allows for specifying an id column?

Current approach:

library(tidyverse)
my_list %>%
  bind_rows() %>%
  pivot_longer(cols = -id) %>%
  filter(!is.na(value)) %>%
  pivot_wider()

Onyambu · Accepted Answer · 2021-06-01T07:11:36.320

3

reduce(my_list, full_join, by='id')
  id x y
1  1 1 6
2  2 2 5
3  3 3 4

If its only 2 dataframes:

invoke(full_join, my_list, by='id')
  id x y
1  1 1 6
2  2 2 5
3  3 3 4

If you are using base R, any of the following should work:

Reduce(merge, my_list)
do.call(merge, my_list)

edited Jun 01 '21 at 07:11

answered Jun 01 '21 at 07:08

Onyambu

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Of course, purrr. Thanks! – deschen Jun 01 '21 at 07:10
And is also considerably faster than my solution. – deschen Jun 01 '21 at 07:18
@deschen if this works, you could consider accepting the answer to close the question – Onyambu Jun 01 '21 at 07:21
Yep, just had to wait a few minutes before being able to accept an answer. – deschen Jun 01 '21 at 07:42

Column bind several list elements based on id variable

1 Answers1