Problem Statement

Create a function,   or show a built-in function,   to count the number of non-overlapping occurrences of a substring inside a string. The function should take two arguments:

It should return an integer count. The matching should yield the highest number of non-overlapping matches. In general, this essentially means matching from left-to-right or right-to-left   (see proof on talk page).

Let's start with the solution:

count = function(haystack, needle)
   {v = attr(gregexpr(needle, haystack, fixed = T)[[1]], "match.length")
    if (identical(v, -1L)) 0 else length(v)}

print(count("hello", "l"))

library(stringr)
print(str_count("hello", fixed("l")))