Tag Archives: Python

How to Completely Uninstall Python on macOS?


You have an issue with a Python version (e.g. the 3.7 version) and want to install another version (e.g. the 3.6 version). In order to install a fresh version you need to uninstall the current version first.


Assume that the current version is 3.7. Replace 3.7 with another version that you installed.

Follow these 3 steps below.

1. Remove the third-party Python 3.7 framework

sudo rm -rf /Library/Frameworks/Python.framework/Versions/3.7

2. Remove the Python 3.7 applications directory

sudo rm -rf "/Applications/Python 3.7"

3. Remove the symbolic links, in /usr/local/bin, that point to this Python version. Ensure that the links exit using below command

ls -l /usr/local/bin | grep '../Library/Frameworks/Python.framework/Versions/3.7'

then run the following commands to remove all the links:

cd /usr/local/bin/
ls -l /usr/local/bin | grep '../Library/Frameworks/Python.framework/Versions/3.7' | awk '{print $9}' | tr -d @ | xargs rm

Installing a new version:

  1. Download a version from https://www.python.org/downloads/mac-osx/, double click the file and follow the instructions.
  2. Verify installation: python3 –version
  3. Install Homebrew from https://brew.sh
  4. Install virtualenv
pip3 install virtualenv
pip3 install virtualenvwrapper

5.  Create and activate a virtual environment

cd /Users/admin/Downloads/training_model/model 
python3 -m virtualenv /Users/admin/Downloads/training_model/model
source bin/activate

Topic 19 – Introduction to Computation and Programming using Python

Why do I need to learn about computation and programming using Python?

Computational thinking and Python are fundamental tools for understanding many modern theories and techniques such as artificial intelligence, machine learning, deep learning, data mining, security, digital imagine processing and natural language processing.

What can I do after finishing learning about computation and programming using Python ?

You will be prepared to learn modern theories and techniques to create  modern  security, machine learning, data mining, image processing or natural language processing software.

That sounds useful! What should I do now?

Please read this John V. Guttag (2013). Introduction to Computation and Programming using Python. 2nd Edition. The MIT Press book.

Alternatively, please watch
- this 6.0001 Introduction to Computer Science and Programming in Python. Fall 2016 course (Lecture Notes) and

- this MIT 6.0002 Introduction to Computational Thinking and Data Science, Fall 2016 course (Lecture Notes).
After finishing reading the book please click Topic 20 - Introduction to Applied Machine Learning to continue.

Topic 4 – Object-Oriented Programming

Why do I need to learn about object-oriented programming?

Because most of modern software are written using object-oriented programming languages. Using object-oriented programming as a tool and more importantly as a problem solving approach will save you a lot of time and cost when you create modern software systems.

Alright! What should I do now?

Please read this Jim Keogh and Mario Giannini (2004). OOP Demystified. McGraw-Hill book.

Is that all?

Unfortunately, the book is not sufficient for writing real world object-oriented software. Although the book already gives you the fundamental concepts of object-oriented programming the examples are only to illustrate the concepts, not to demonstrate real world situations.

We recommend that you read it first because it introduces basic concepts of object-oriented programming very well. It helps you to distinguish object-oriented concepts from procedural programing concepts very clearly so that you could read other books to dig into real world object-oriented programming in a proper way.

Please read this RB Whitaker (2017). The C# Player's Guide. Starbound Software book to learn how to apply object-oriented concepts to creating real world software using a specific object-oriented programming language (i.e. C# language).
After that please take a quick look at  
- this Joseph Albahari and Eric Johannsen (2020). C# 8.0 in a Nutshell: The Definitive Reference. O'Reilly Media book or 
- this Herbert Schildt (2010). C# 4.0 The Complete Reference. McGraw Hill book so that you can refer to a specific topic that needs more study when developing real world software.

I hear that there are many object-oriented programming languages such as C++, C#, Java, PHP, Objective-C, Swift, Python, Ruby. How many object-oriented programming languages do I need to know?

You should learn as many as possible. However, in this stage, we recommend that you learn only C++ or C# or Java.
C++ is the most used language for creating software systems that need high performance, including games, operating systems, compilers, database management systems, web browsers, graphics editors, medical and engineering applications.
Java and C# are the most used languages for creating enterprise systems.
- If you are required or prefer to learn C++, please read this Bjarne Stroustrup (2013). The C++ Programming Language. Pearson Education book.
- If you are required or prefer to learn Java, please read this Herbert Schildt (2019). Java: The Complete Reference. McGraw-Hill Education book.
After that please read 
- this Matt Weisfeld (2019). The Object-Oriented Thought Process. Pearson Education book and 
- this Bertrand Meyer (1997). Object-Oriented Software Construction. Prentice Hall book to get deeper understanding about object-oriented concepts and learn how to design software using object-oriented approach more efficiently.
After finishing the books please click Topic 5 - Introduction to Windows Programming to continue.

Topic 2 – Introduction to Programming

Why do I need to know a programming language?

Because you will develop your software using a programming language. A programming language is a language that both you and a computer will understand. It's a tool for you to express what you want a computer to do. It's a tool for you to write instructions of your computer programs. Without knowledge of a programming language, you cannot develop any software.

I hear about many programming languages such as C, C++, C#, Objective-C, Java, Swift, Ruby, Python, JavaScript, PHP, F#, Kotlin,  Clojure, Go, or Lisp. How many programming languages should I know?

As many as possible. However, at this stage, you should learn about structure of a computer program and a procedure language (e.g. C or C++) first.

What should I do now?

Please read this Stephen Prata (2011). C Primer Plus. Pearson book.
Alternatively, you can read from Chapter 1 to Chapter 9 of this Stephen Prata (2012). C++ Primer Plus. Pearson book.
Alternatively, you can read from Chapter 1 to Chapter 9 of this John M. Zelle (2017). Python Programming: An Introduction to Computer Science. Franklin, Beedle & Associates book.

Alternatively, you can read from Chapter 1 to Chapter 11 of this Charles Severance (2013). Python for Informatics: Exploring Information book.
Alternatively, you can read 
- this David Flanagan (2020). JavaScript: The Definitive Guide. O'Reilly Media book, and
- this Kyle Simpson (2015). You Don't Know JS. O'Reilly Media book.
Alternatively, you can read from Chapter 1 to Chapter 11 of this Chris Pine (2013). Learn to Program: The Facets of Ruby Series. The Pragmatic Bookshelf book.
Alternatively, you can read 
- this Alan A. A. Donovan and Brian W. Kernighan (2015). The Go Programming Language. Addison-Wesley Professional book, and
- this Nathan Youngman and Roger Peppe (2018). Get Programming with Go. Manning Publications book.
After that please read this Harold Abelson and Gerald Jay Sussman (1996). Structure and Interpretation of Computer Programs. The MIT Press book to get vocabularies and in-depth knowledge about programming, especially the relationship between mathematics and programming, and ideas of functional programming and logic programming.
Alternatively please read these Course Notes.
After finishing the books please click Topic 3 - Introduction to Algorithms and Data Structures to continue.