Add Check For A Substring Match as an elixir til

elixir/check-for-a-substring-match.md

@@ -0,0 +1,20 @@
+# Check For A Substring Match
+
+Using Erlang's `:binary.match` function, you can easily check if a string
+has a matching substring.
+
+```elixir
+> :binary.match("all food is good", "foo")
+{4, 3}
+> :binary.match("all food is good", "bar")
+:nomatch
+```
+
+As you can see, the return value on a successful match is a tuple with the
+index of where the match starts and the length of the match. If there is no
+match, the `:nomatch` atom is returned.
+
+See the [`match/2` and `match/3`
+docs](http://erlang.org/doc/man/binary.html#match-2) for more details.
+
+[source](http://stackoverflow.com/questions/35551072/how-to-find-index-of-a-substring)