Almost everybody has written about the Python sets and a few ones about the frozensets. Even thought the literature is still too much pragmatic and it lacks of real examples to figure out daily problems, something that a Python coder practices almost unwittingly. Yesterday I had an Eureka moment trying to find the right problem to show how frozensets can be used. This post shows how to build a full text search engine through an invert index using a few lines of Python and plenty of memory RAM.

Recently the DI pattern has appeard in front of me as a design pattern, no matters how but it challenged me. In this post I want to review the usage of the DI pattern, the use of this pattern using a library and at last compare it with more traditional patterns such as the global class pattern.