How To Install Python Packages – Part II

See the first part in this series here.

Importing Python packages

As we know Python is an open-source project. The Python developers community make their codes available for others in the form of packages under the open source license.

You will have access to some in-built packages such as Pandas, NumPy by default when you installed Python.

You can import these packages in your code using the following syntax.

# Import a Python package
Import pandas

Suppose we want to design a package (a collection of modules) for the uniform handling of various trading strategies and their data. There are many different data files based on data frequencies, so we may need to create and maintain a growing collection of modules for the conversion between the various data frequencies. Also, there are many different strategies and operations that we might need to perform. All of this put together means we would have to write a never-ending stream of modules to handle the combinatorics of data, strategies, and operations.

When importing the package, Python searches through the directories in sys.path looking for the package subdirectory. The __init__.py file is required to make Python treat the directories as containing packages. If we are to use this package, we can do so in the following manner:

import strats.data.equity
import strats.strategies.statisticalarbitrage

Above statements loads the equity and statisticalarbitrage modules from the data and strategies sub-packages respectively under the strats package. So far, we understood how to import the packages, but how to install Python packages? Is there even a need to install them? Let’s find out in the next section.

Stay tuned for the next installment in this series. The authors will discuss what to do when the Python packages do not get installed.