Exclude zero terms from being counted for `combn` in a function in r

Question

I want to run the following function

Proposed <- function(N_b,N_l,m,A,x.sqr,e_1,e_2,e_3,e_4,e_5,K_g,a,b,c,d) {
  e <- data.frame(e_1,e_2,e_3,e_4,e_5,N_l