R: How to add two data frames with different columns

Question

I would like to merge two data frames with different columns while columns of the same variable should be added.

This is an example of what I have (the real data frames have about 200 columns each):

A: document v1 v2 v3
1  text1    1  0  0
2  text2    0  0  1
3  text3    0  0  0

B: document v2 v3 v4
1  text1    2  0  1
2  text2    0  1  0
3  text3    1  1  0

What I like to get is:

C: document v1 v2 v3 v4
1  text1    1  2  0  1
2  text2    0  0  2  0
3  text3    0  1  1  0

I tried some variants of merge, bind and join but I can't quite figure it out. Any help would be very welcome!

Answer 1

We get the datasets in a list, rbind it together, grouped by 'document' get the sum of each column

library(tidyverse)
list(A, B) %>%
    bind_rows %>% 
    group_by(document) %>% 
    summarise_all(sum, na.rm = TRUE)
# A tibble: 3 x 5
#  document    v1    v2    v3    v4
#  <chr>    <int> <int> <int> <int>
#1 text1        1     2     0     1
#2 text2        0     0     2     0
#3 text3        0     1     1     0