What are the best practices for using iterators and iterables in Python?

What are the best practices for using iterators and iterables in Python?

When using iterators and iterables in Python, it's important to follow best practices like using generator expressions for memory efficiency, implementing the iterator protocol correctly, and avoiding side effects in your iteration logic.

Can you explain the iterator protocol?

The iterator protocol consists of two methods: __iter__() which returns the iterator object itself, and __next__() which returns the next value from the iterator. If there are no more items, __next__() should raise a StopIteration exception.

What are generator expressions and how do they differ from list comprehensions?

Generator expressions are similar to list comprehensions but use parentheses instead of brackets. They generate items one at a time and are more memory efficient since they don't store the entire list in memory.

How can I create a custom iterator?

To create a custom iterator, define a class with __iter__() and __next__() methods. This allows you to control the iteration process and define how the items are generated.

What are some common pitfalls to avoid when using iterators?

Common pitfalls include modifying the iterable while iterating, not handling StopIteration properly, and using iterators in a way that leads to unexpected behavior, such as reusing an exhausted iterator.