Before we finish this chapter, we will very briefly touch on a completely different, yet very sought-after topic, that is, getting data from Twitter. In case you want to apply predictive models, you will need to link the Twitter data to a variable you want to predict, which normally comes from other data. However, something you can easily do is measure the sentiment around a topic using the techniques we showed in a previous section.

The twitteR package actually makes it very easy for us to retrieve Twitter data. To do so, we will create a Twitter App within Twitter, which will give us access to the data feed. To accomplish this, we need to generate four strings within your Twitter account that will be the keys to using the API. These keys are used to validate your permissions and monitor your usage in general. Specifically, you need four strings...