Pre-processing, or more generally processing the data, is an integral part of most machine learning exercises. A dataset that you start out with is seldom going to be in the exact format against which you'll be building your machine learning models; it will invariably require a fair amount of cleansing in the majority of cases. In fact, data cleansing is often the most time-consuming part of the entire process. In this section, we will briefly highlight a few of the top data processing steps that you may encounter in practice.