Book Image

Python Data Analysis - Second Edition

By : Ivan Idris
Book Image

Python Data Analysis - Second Edition

By: Ivan Idris

Overview of this book

Data analysis techniques generate useful insights from small and large volumes of data. Python, with its strong set of libraries, has become a popular platform to conduct various data analysis and predictive modeling tasks. With this book, you will learn how to process and manipulate data with Python for complex analysis and modeling. We learn data manipulations such as aggregating, concatenating, appending, cleaning, and handling missing values, with NumPy and Pandas. The book covers how to store and retrieve data from various data sources such as SQL and NoSQL, CSV fies, and HDF5. We learn how to visualize data using visualization libraries, along with advanced topics such as signal processing, time series, textual data analysis, machine learning, and social media analysis. The book covers a plethora of Python modules, such as matplotlib, statsmodels, scikit-learn, and NLTK. It also covers using Python with external environments such as R, Fortran, C/C++, and Boost libraries.
Table of Contents (22 chapters)
Python Data Analysis - Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface
Key Concepts
Online Resources

Dealing with dates


Dates are complicated. Just think of the Y2K bug, the pending Year 2038 problem, and the confusion caused by time zones. It's a mess. We encounter dates naturally when dealing with the time-series data. Pandas can create date ranges, resample time-series data, and perform date arithmetic operations.

Create a range of dates starting from January 1 1900 and lasting 42 days, as follows:

print("Date range", pd.date_range('1/1/1900', periods=42, freq='D')) 

January has less than 42 days, so the end date falls in February, as you can check for yourself:

Date range <class 'pandas.tseries.index.DatetimeIndex'>
[1900-01-01, ..., 1900-02-11]
Length: 42, Freq: D, Timezone: None

The following table from the Pandas official documentation (refer to http://pandas.pydata.org/pandas-docs/stable/timeseries.html#offset-aliases) describes the frequencies used in Pandas:

Short code

Description

B

Business day frequency

C

Custom business day frequency (experimental...