Generators

Generators are a very useful tool but they come with a set of rules to keep in mind.

First, let’s explore the advantages of generators:

• Generators are often simpler to write than list-generating functions. Instead of having to declare a list, list.append(value), and return, you only need yield value.
• Memory usage. Items can be processed one at a time, so there is generally no need to keep the entire list in memory.
• Results can depend on outside factors. Instead of having a static list, you generate the value when it is being requested. Think of processing a queue/stack, for example.
• Generators are lazy. This means that if you’re using only the first five results of a generator, the rest won’t even be calculated. Additionally, between fetching the items, the generator is completely frozen.

The most important disadvantages are:

• Results are available only once. After processing the results of a...