What is a Bag-of-Words Model?

A Bag-of-Words model is a class of models used for text mining tasks that is based on the frequency of words appearing within the corpus of documents. It does not consider the order in which the words occur throughout the respective documents, only their existence. The basic structure for a Bag-of-Words model is to have each word within the vocabulary as a separate feature. Each document is usually converted from its raw state into a numeric vector, where each element of the vector is a representation for the corresponding word within the vocabulary.