---
title: Constants
layout: gem-single
name: dry-core
---

A list of constants you can use to avoid memory allocations or identity checks.

* `EMPTY_ARRAY`
* `EMPTY_HASH`
* `EMPTY_OPTS`
* `EMPTY_SET`
* `EMPTY_STRING`
* `Undefined` - A special value you can use as a default to know if no arguments were passed to you method
