get all combinations of a vector of letters

get_all_combs.R

# vector
x = c('1','2','3')

# i want a vector of all combinations of these strings, but i want to be able to say I want all 2 way or three way combs

# two-way is easy
get_all_combs <- function(x){
  return(expand.grid(x,x) %>% 
           filter(Var1 != Var2) %>% 
           unite(., 'y', everything(), sep = '') %>% 
           pull(y))
}

get_all_combs(x)

# becomes much harder with three way


get_all_combs <- function(x, vec_len = 2){
  # set command
  return(expand.grid(rep(list(x), vec_len)) %>%
           filter(apply(., 1, function(x)length(unique(x))) == vec_len) %>% 
           unite(., 'y', everything(), sep = '') %>% 
           pull(y))
}

# bit gnarly but gets there - the apply is very stressful but not sure how else to do it
get_all_combs(x, vec_len = 2)