How to check if an item exists in an Elixir list or tuple?

Question

This is seemingly simple, but I can't seem to find it in the docs. I need to simply return true or false if an item exists in a list or tuple. Is Enum.find/3 really the best way to do this?

Enum.find(["foo", "bar"], &(&1 == "foo")) != nil 

Answer 1

You can use Enum.member?/2

Enum.member?(["foo", "bar"], "foo") # true 

With a tuple you will want to convert to to a list first using Tuple.to_list/1

Tuple.to_list({"foo", "bar"}) # ["foo", "bar"] 

Answer 2

Based on the answers here and in Elixir Slack, there are multiple ways to check if an item exists in a list. Per answer by @Gazler:

Enum.member?(["foo", "bar"], "foo") # true 

or simply

"foo" in ["foo", "bar"] # true 

or

Enum.any?(["foo", "bar"], &(&1 == "foo") # true 

or if you want to find and return the item instead of true or false

Enum.find(["foo", "bar"], &(&1 == "foo") # "foo" 

If you want to check a tuple, you need to convert to list (credit @Gazler):

Tuple.to_list({"foo", "bar"}) # ["foo", "bar"] 

But as @CaptChrisD pointed out in the comments, this is an uncommon need for a tuple because one usually cares about the exact position of the item in a tuple for pattern matching.