Unique combination of all elements from two (or more) vectors

Question

I am trying to create a unique combination of all elements from two vectors of different size in R.

For example, the first vector is

a <- c(\"ABC\         


        

Answer 1

Since version 1.0.0, tidyr offers its own version of expand.grid(). It completes the existing family of expand(), nesting(), and crossing() with a low-level function that works with vectors.

When compared to base::expand.grid():

Varies the first element fastest. Never converts strings to factors. Does not add any additional attributes. Returns a tibble, not a data frame. Can expand any generalised vector, including data frames.

a <- c("ABC", "DEF", "GHI")
b <- c("2012-05-01", "2012-05-02", "2012-05-03", "2012-05-04", "2012-05-05")

tidyr::expand_grid(a, b)

   a     b         
         
 1 ABC   2012-05-01
 2 ABC   2012-05-02
 3 ABC   2012-05-03
 4 ABC   2012-05-04
 5 ABC   2012-05-05
 6 DEF   2012-05-01
 7 DEF   2012-05-02
 8 DEF   2012-05-03
 9 DEF   2012-05-04
10 DEF   2012-05-05
11 GHI   2012-05-01
12 GHI   2012-05-02
13 GHI   2012-05-03
14 GHI   2012-05-04
15 GHI   2012-05-05