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

Tidying when multiple variables are stored as a single column

Tidy datasets must have a single column for each variable. Occasionally, multiple variable names are placed in a single column with their corresponding value placed in another.

In this recipe, we identify the column containing the improperly structured variables and pivot it to create tidy data.

How to do it…

  1. Read in the restaurant inspections dataset, and convert the Date column data type to datetime64:
    >>> inspections = pd.read_csv('data/restaurant_inspections.csv',
    ...     parse_dates=['Date'])
    >>> inspections
                                  Name  ...
    0                E & E Grill House  ...
    1                E & E Grill House  ...
    2                E & E Grill House  ...
    3                E & E Grill House  ...
    4                E & E Grill House  ...
    ..                             ...  ...
    495  PIER SIXTY ONE-THE LIGHTHOUSE  ...
    496...