Book Image

Pandas 1.x Cookbook - Second Edition

By : Matt Harrison, Theodore Petrou
Book Image

Pandas 1.x Cookbook - Second Edition

By: Matt Harrison, Theodore Petrou

Overview of this book

The pandas library is massive, and it's common for frequent users to be unaware of many of its more impressive features. The official pandas documentation, while thorough, does not contain many useful examples of how to piece together multiple commands as one would do during an actual analysis. This book guides you, as if you were looking over the shoulder of an expert, through situations that you are highly likely to encounter. This new updated and revised edition provides you with unique, idiomatic, and fun recipes for both fundamental and advanced data manipulation tasks with pandas. Some recipes focus on achieving a deeper understanding of basic principles, or comparing and contrasting two similar operations. Other recipes will dive deep into a particular dataset, uncovering new and unexpected insights along the way. Many advanced recipes combine several different features across the pandas library to generate results.
Table of Contents (17 chapters)
15
Other Books You May Enjoy
16
Index

Selecting DataFrame rows and columns simultaneously

There are many ways to select rows and columns. The easiest method to select one or more columns from a DataFrame is to index off of the DataFrame. However, this approach has a limitation. Indexing directly on a DataFrame does not allow you to select both rows and columns simultaneously. To select rows and columns, you will need to pass both valid row and column selections separated by a comma to either .iloc or .loc.

The generic form to select rows and columns will look like the following code:

df.iloc[row_idxs, column_idxs]
df.loc[row_names, column_names]

Where row_idxs and column_idxs can be scalar integers, lists of integers, or integer slices. While row_names and column_names can be the scalar names, lists of names, or names slices, row_names can also be a Boolean array.

In this recipe, each step shows a simultaneous row and column selection using both .iloc and .loc.

How to do it…

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