Unable to Run Python 3 After Homebrew Installation

Question

After installing Homebrew using the script on their homepage and checking if everything was alright with brew doctor, I issued brew install python3

Answer 1

I think I detected which is the problem.

I guess that, in a certain moment, you had installed python from the official site instead of via Homebrew. In my case, I installed via the official website Python 3.6.4. A few months later, I wanted to upgrade it, and noticed that it was very complex. So, I decided to move to Homebrew. Open a terminal window and let's try to fix this: 1. First, let's uninstall previous Python versions:

    sudo rm -rf /Library/Frameworks/Python.framework
    sudo rm -rf /usr/local/bin/python3

2. Then, remove the previous frameworks from the $PATHvariable:

    nano ~/.bash_profile

You will see something like that:

    # Setting PATH for Python 2.7
    # The original version is saved in .bash_profile.pysave
    PATH="/Library/Frameworks/Python.framework/Versions/2.7/bin:${PATH}"
    export PATH

    # Setting PATH for Python 3.6
    # The original version is saved in .bash_profile.pysave
    PATH="/Library/Frameworks/Python.framework/Versions/3.6/bin:${PATH}"
    export PATH`

This is the problem: These paths don't exist. Comment the $PATH editions (or erase them):

    # Setting PATH for Python 2.7
    # The original version is saved in .bash_profile.pysave
    # PATH="/Library/Frameworks/Python.framework/Versions/2.7/bin:${PATH}"
    # export PATH

    # Setting PATH for Python 3.6
    # The original version is saved in .bash_profile.pysave
    # PATH="/Library/Frameworks/Python.framework/Versions/3.6/bin:${PATH}"
    # export PATH

3. Restart the computer and install via Homebrew Python 2 and 3:

    brew update
    brew install python
    brew install python3

This worked for me. Now, if type python3 --version I get Python 3.7.0, and everything works fine :)