# `KeyError`
[🔗](https://github.com/elixir-lang/elixir/blob/v1.20.0-rc.3/lib/elixir/lib/exception.ex#L2151)

An exception raised when a key is not found in a data structure.

For example, this is raised by `Map.fetch!/2` when the given key
cannot be found in the given map:

    iex> map = %{name: "Alice", age: 25}
    iex> Map.fetch!(map, :first_name)
    ** (KeyError) key :first_name not found in:
    ...

The following fields of this exception are public and can be accessed freely:

  * `:term` (`t:term/0`) - the data structure that was searched
  * `:key` (`t:term/0`) - the key that was not found

---

*Consult [api-reference.md](api-reference.md) for complete listing*