It might come as a surprise, or not, textual data represents the greatest part of the overall data accessible to companies and data analysts. Textual data is often available only in unstructured form. Imagine, for instance, an e-mail, a company memo, or a post on a blog. What they have in common is that text is mostly presented in the form of words arranged in sentences arranged in paragraphs. More complex documents are also composed of sub-sections, sections, and chapters. Humans derive meaning from this basic structure and the relationships between these elements. But for machines to classify documents and extract meaning, text preprocessing is required.
There are several usual steps in the preprocessing of textual documents for classification. These include:
