> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/sidef-lang/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/sidef-lang/programming_tasks/j/jewels_and_stones.md).

# Jewels and stones

```ruby
func countJewels(s, j) {
    s.chars.count { |c|
        j.contains(c)
    }
}

say countJewels("aAAbbbb", "aA")    #=> 3
say countJewels("ZZ", "z")          #=> 0
```