Uproot Tutorial: Glossary

Uproot is a fast and lightweight Python package for reading and writing ROOT files.

Uproot is designed to work efficiently with jagged arrays of data.

Opening and navigating files in Uproot isn’t that different from doing so in ROOT.

Use .keys() to see the contents of a file.

Use the form file['key'] to access an object inside a file.

TTrees are tables of data.

Trees are made of branches, which are columns in the table.

Each row represents an event.

Use the bins and/or range parameters to improve histogram binning.

Make sure your axes are labeled.

Jagged arrays must be flattened before histogramming.

Selections are created by comparisons on arrays and are represented by masks (arrays of Boolean values).

Selections are applied by acting like a mask is an array index.

Avoid for loops whenever possible in analysis (especially in Python).

Vector has allows you to manipulate arrays of four-vectors.

Uproot can be used to do real physics analyses.

There are many packages for fitting, and this just one very simple example.

Python and many Python packages have a huge userbase and are well supported by documentation, tutorials, and the community.