- Structure: A dictionary consists of key-value pairs that are separated from other key-value pairs by commas. Inside the key-value pair, key and value is separated by a colon (:). First few examples below will clearly demonstrate this.
- Composite Nature: List is a very useful composite data structure meaning it can hold multiple types of data. You can also call it a data sequence.
- No order: Unlike lists and tuples there is no order or indexing inside a dictionary. You can think of key-value pairs inside a dictionary as if they are mixed in a bag. Although this can be a little confusing or restricting sometimes it is actually straightforward. There is no first or second key in a dictionary, they just randomly exist. Python’s dictionary structure is optimized for performance in a way that a value is accessed through its key.