pandas.Series.sparse.fill_value

Series.sparse.fill_value

Elements in data that are fill_value are not stored.

For memory savings, this should be the most common value in the array.

© 2008–2012, AQR Capital Management, LLC, Lambda Foundry, Inc. and PyData Development Team
Licensed under the 3-clause BSD License.
https://pandas.pydata.org/pandas-docs/version/0.25.0/reference/api/pandas.Series.sparse.fill_value.html