PyData Berlin 2014 Low-rank approximations of data matrices have become an important tool in machine learning and data mining. They allow for embedding high dimensional data in lower dimensional spaces and can therefore mitigate effects due to noise, uncover latent relations, or facilitate further processing. These properties have been proven successful in many application areas such as bio-informatics, computer vision, text processing, recommender systems, social network analysis, among others. Present day technologies are characterized by exponentially growing amounts of data. Recent advances in sensor technology, internet applications, and communication networks call for methods that scale to very large and/or growing data matrices. In this talk, we will describe how to efficiently analyze data by means of matrix factorization using the Python Matrix Factorization Toolbox (PyMF) and HDF5. We will briefly cover common methods such as k-means clustering, PCA, or Archetypal Analysis which can be easily cast as a matrix decomposition, and explain their usefulness for everyday data analysis tasks.