An expression in Python is a piece of code that produces a result or value. Most often, we think of expressions that are used to perform mathematical operations within our code. However, there are a multitude of expressions used for other purposes as well. In Chapter 2, we covered the details of String manipulation, sequence and dictionary operations, and touched upon working with sets. All of the operations performed on these objects are forms of expressions in Python. Other examples of expressions could be pieces of code that call methods or functions, and also working with lists using slicing and indexing.
