Functional Python Programming

Using lists, dicts, and sets

A Python sequence object, like a list, is iterable. However, it has some additional features. We'll think of it as a materialized iterable. We've used the tuple() function in several examples to collect the output of a generator expression or generator function into a single tuple object. We can also materialize a sequence to create a list object.

In Python, a list display offers simple syntax to materialize a generator: we just add the [] brackets. This is ubiquitous to the point where the distinction between generator expression and list comprehension is a subtlety of little practical importance.

The following is an example to enumerate the cases:

>>> range(10)
range(0, 10)
>>> [range(10)]
[range(0, 10)]
>>> [x for ...