class: center, middle, inverse, title-slide # Comparing texts ## <br><br> Introduction to Data Science ### <a href="https://introds.org/">introds.org</a> ### <br> Dr. Mine Çetinkaya-Rundel --- layout: true <div class="my-footer"> <span> <a href="https://introds.org" target="_blank">introds.org</a> </span> </div> --- ## What is a document about? - Term frequency - Inverse document frequency `$$idf(\text{term}) = \ln{\left(\frac{n_{\text{documents}}}{n_{\text{documents containing term}}}\right)}$$` tf-idf is about comparing **documents** within a **collection**