An asynchronous example

To keep things simple but still interesting, let's write a tool that, given a text file, will count the occurrences of a given word. This example builds on the silly coroutine that we implemented in the previous section, adding some useful behavior to it.

It should be noted that, at least on a Linux or Mac OS X machine, one can achieve the same result very simply using the grep command, as we will see. Let's start by downloading a significantly large text that we will use as input data for our experiments. Let's just choose a public domain book from Project Gutenberg: War and Peace by Leo Tolstoy, which is freely available at

The following snippet shows how we can download ...

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