复制观察 r 中另一列中每一行的列

Question

My question may be misleading but is simpler with an example:

imagine I have a dataframe of countries

Departure 

US
FRANCE
BRESIL

I want something like this:

Departure      Arrival

US             US
FRANCE         US
BRESIL         US
US             FRANCE
FRANCE         FRANCE
BRESIL         FRANCE
US             BRESIL
FRANCE         BRESIL
BRESIL         BRESIL

But I have actually way more destinations. I think there is a simple way to do it but I can't figure it out. Thanks!

Answer 1

You want something like

expand.grid(Departure = Departure, Arrival = Departure)

with your data:

Departure <- c("US", "FR", "BR")

expand.grid(
    Departure = Departure,
    Arrival = Departure
)
#>   Departure Arrival
#> 1        US      US
#> 2        FR      US
#> 3        BR      US
#> 4        US      FR
#> 5        FR      FR
#> 6        BR      FR
#> 7        US      BR
#> 8        FR      BR
#> 9        BR      BR

^{Created on 2021-03-25 by the reprex package (v1.0.0)}