R: apply a function to every element of two variables respectively

Question

I have a function with two variables x and y:

fun1 <- function(x,y) {
  z <- x+y
  return(z)
}

The function work fine by itself:

Answer 1

Using dplyr for this problem, as you've described it, is weird. You seem to want to work with vectors, not data.frames, and dplyr functions expect data.frames in and return data.frames out, i.e. it's inputs and outputs are idempotent. For working with vectors, you should use outer. But dplyr could be shoehorned into doing this task...

# define variables
Lx  <- c(1:56)
Ly <- c(1:121)
dx <- as.data.frame(Lx)
dy <- as.data.frame(Ly)

require(dplyr)
require(magrittr)  # for the %<>% operator

# the dplyr solution
(dx %<>% mutate(dummy_col = 1)) %>% 
     full_join(
         (dy %<>% mutate(dummy_col = 1)), by='dummy_col') %>% 
     select(-dummy_col) %>% 
     transmute(result = Lx + Ly)