Lesson 2: Naive Bayes

Lesson 2 of the Udacity Course UD120 – Intro to Machine Learning deals with Naive Bayes classification. Mini project For the mini project you should fork https://github.com/udacity/ud120-projects and clone it. It is recommended to install a python 2.7 64bit version because ML is heavy data processing and can easily rip up more than 2GB of…

Support Vector Machines

The term Support Vector Machines or SVM is a bit misleading. It is just a name for a very clever algorithm invented by two Russians. in the 1960s. SVMs are used for classification and regression. SVM do that by finding a hyperplane between two classes of data which separates both classes best.   print(“Start training”)…

Linear Algebra with numpy

Numpy is a package for scientific computing in Python. It is blazing fast due to its implementation in C. It is often used together with pandas, matplotlib and Jupyter notebooks. Often these packages are referred to as the datascience stack. Installation You can install numpy via pip pip install numpy Basic Usage In the datascience…

Python pip and virtualenv

After working for a couple of years with Python and external dependencies I’ve ran again and again into the same kind of problems. Bad habits Say you have a global python installation under e.g. C:\Python36 on Windows. When you start working on your first python project you want to use external packages and you encounter…

New Blog Post

Python Type Checking

Python is a dynamically typed language which makes it easy and fun to program. But sometimes -especially in bigger projects- it can become quite cumbersome when you just receive errors at run time. Given the hypothetical example where we define a function which multiplies integer: def multiply(a, b): return a * b print(multiply(“I”, “You”)) It…

The Normal Distribution

Diving deeper into data science I started to brush up my knowledge about math especially statistics. The Mother of all Distributions The normal distribution was formulated by Carl Friedrich Gauß in 1809 and can be implemented in Python like the following : def normal_distribution_pdf(x, mu=0, sigma=1): sqrt_two_pi = math.sqrt(2*math.pi) return (1 / (sqrt_two_pi * sigma))…

What is Cross-Validation in Data Science?

Motivation Cross-validation is a technique to validate the quality of your machine learning model. For validating your model you split your training data into a training and a test data set. ———————————————– | | | | training data | test data | | | | ———————————————– More training data means a better model, more test…

Introduction to Jupyter Notebook

JuPyteR Do You know the feeling of being already late to a party when encountering something new? But when you actually start telling others about it, you realize that it is not too common knowledge at all, e.g. Jupyter Notebooks. What is a Jupyter notebook? In my own words: a browser-based document-oriented command line style…

pip optional dependencies

Sometimes you want to make your python package usable for different situations, e.g. flask or bottle or django. If You want to minimize dependencies You can use an optional dependency in setup.py: extras_require={ ‘flask’: [‘Flask>=0.8’, ‘blinker>=1.1’] } Now you can install the library with: pip install raven[flask]