Set Python’s default version to 3.x on OS X

Open ~/.bash_profile file.

$ nano ~/.bash_profile

Then put the alias as follows:

alias python='python3'

Now save the file and then run the ~/.bash_profile file.

$ source ~/.bash_profile

Congratulation !!! Now, you can use python3 by typing python.

$ python --version
Python 3.8.1

Upgrade pip command

$ pip3 install --upgrade pip

Install virtualenv

$ pip3 install virtualenv

ใช้ brew ติดตั้ง python

$ brew install python