"E: Unable to locate package python3-pip"
For Ubuntu 18.04 with python 3.6.5 the python-pip package will install after :
sudo add-apt-repository universesudo apt-get updateWhich is enabling the category universe
deb http://archive.ubuntu.com/ubuntu bionic main universedeb http://archive.ubuntu.com/ubuntu bionic-security main universe deb http://archive.ubuntu.com/ubuntu bionic-updates main universe
Following a clean install of Ubuntu 18.04 (via Vagrant) the following installed successfully with no issues:
sudo apt-get update sudo apt-get install -y python3-pipNote that the Ubuntu 18.04 download today shipped with Python 3.6.8 installed. This may vary by the time of your reading this post.
First update then install python3-pip.So following two commands should work.
sudo add-apt-repository universesudo apt-get updatesudo apt-get install python3-pip