# Category: Source code

## Market Basket Analysis – Mining Frequent Pairs in Python

Have you ever asked yourself how the store managers decide on product shelf placement in retail stores? There must be some strategy behind it, right? It can’t be just a random choice. Almost on daily basis, you receive product purchase recommendations from variety of sources where you have left your “digital fingerprint”. In many cases these ...

## Bloom Filter Example in Python

The title might also have been, “how to reduce 10 Gb of data to 1 single Megabyte”. BigData is only going to get bigger in the future. Our challenge, among others, is to find efficient methods and algorithms to (quickly) deal with wast amounts of data, extract meaningful information and to find ways how to ...

## From Recursion to Tail Recursion in Scala

#scala #recursion #optimization

## Twitter API Streaming in Python

Maybe the easiest way to connect to Twitter API and to stream tweets, is using Python and Tweepy. You can install Tweepy using pip: Tweepy is an open source library and you can check the source here. Maybe, take a peak at StreamListener class and see what additional options are available. ‘Nuff said. Here’s the ...

## Google’s PageRank Algorithm in Python

Have you ever asked yourself how google ranks the pages when you search something on google.com? If yes, have a look at PageRank algorithm definition. I’ll not go into much details here, but to give you an idea, the World Wide Web can be seen as a large graph, consisting of pages as nodes and ...

## A Star (A*) Algorithm with Caching – Java Implementation

Route calculation is computationally an expensive operation. There are several ways how to reduce computational load on the backend. I’ll show you how I optimized my computational resources. There are times where a bunch of people is heading to the same event using the same or at least similar paths. Following this logic, it is ...

## A Star (A*) Algorithm Implementation in Java

A* algorithm can be seen as an heuristic extension of Dijkstra’s. Whereas in the Dijkstra’s priority-queue ordering is based only on the distance from the start node to the current, A* algorithm additionally calculates the distance from the current node to the goal-node. Thus the ordering in the priority queue is different and the algorithm ...

## Dijkstra’s Algorithm implementation in Java

The Breadth First Search (BFS) algorithm basically checks only if there is a path from node A to node B. It’ doesn’t necessarily find the shortest path between two graph nodes. Here comes Dijkstra into the game. Dijkstra’s algorithm finds the shortest possible route between two graph nodes. The main difference between Dijkstra and BFS ...

## PHP MySql Radius Search WebService – Source

Sometimes you need your mysql radius-search backend fast! This is how I do it on the fly. For more infos regarding radius search check this link. Enjoy the source and have fun…

## Anonymous Web Scraping with Python Selenium PhantomJS Xpath and TOR

Using pure selenium methods to extract data from metasearch websites is quite tricky and uses a lot of CPU resources. I have spent significant amount of time with selenium built-in methods with python and have a feeling that the development is quite tedious, time consuming and prone to bugs. Selenium’s WebElement objects are not flexible, ...