Performing a one to many join in R dplyr-CodePudding

How to do a one to one-to-many join without any keysin r using dplyr? I have two tables:

origin<-tribble(~"o",
     1,2)

destination<-tribble(~"d",
     5,
     6,
     7)

I want to merge both of them without any keys like the following:

od<- tribble(~"o",~"d",
        1,5,
        1,6,
        1,7,
        2,5,
        2,6,
        2,7)

Can anyone help me out with this?

CodePudding user response：

You can use slice and rep to repeat the rows in origin based on the length of destination. Then, inside of bind_cols, we can create a list and repeat the values in destination based on the length of origin; then, bind them together.

library(tidyverse)

origin %>%
  slice(rep(1:n(), each = nrow(destination[, 1]))) %>%
  bind_cols(., d = unlist(rep(
    c(destination[, 1]), times = nrow(origin)
  )))

Output

# A tibble: 6 × 2
      o     d
  <dbl> <dbl>
1     1     5
2     1     6
3     1     7
4     2     5
5     2     6
6     2     7

CodePudding user response：

tidyr::crossing and expand_grid can give you a cross join of two dataframes.

tidyr::crossing(origin, destination)
#tidyr::expand_grid(origin, destination)

#     o     d
#  <dbl> <dbl>
#1     1     5
#2     1     6
#3     1     7
#4     2     5
#5     2     6
#6     2     7