I have two vectors like this:
f1=c('a','b','c','d')
e1=c('e','f','g')
There is 4^3 different permutations of them. I need to create all of possible permutations of them in R softeware.for example;
(1):
a e
a f
a g
(2):
a e
a f
b g
...
Moreover, my real data are very huge and I need speed codes.