14. Installing Packages — Lecture

Installing Packages

pip: Package Installer for Python

installing 3rd party libraries (packages) basically requires copying files into the Python installation (whichever directory you want)

• can be done manually, but again, tedious
• instead can use another app that is installed alongside Python
  • pip
    • easily install, update and remove packages
      • uses the Python Package Index https://pypi.org
        • official 3rd party repository for Python
        • a repository of over 200,000 Python packages!

Installing Packages with pip

• activate the virtual environment first (sets your PATH)

<aside> 💡 pip install package_name

• can even specify versions

  • pip install package_name==1.3.2
  • pip install package_name<=1.2
  • pip install package_name>2.0 </aside>

• once you have decided on a specific version of a package for your project you should always use same version number if creating a new environment for the same project

  • otherwise you could end up breaking your own code!

The requirements.txt File

• use a file, alongside your code, to keep track of required packages and versions

  

  <aside> 💡 pip install –r requirements.txt

  • easier (install everything with one command)
  • reproducibility / consistency
  • documentation </aside>

• for this course a requirements.txt file is available in your downloads

  • defines (and pins) all specific libraries we'll need
  • please use it so we're all using the same library versions (functionality can change from version to version)
    • will install many libraries (and their dependencies)
      • requests
      • pytz
      • numpy
      • pandas

Summary of Steps

• create a new virtual environment