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

Accessing databases from Pandas


We can give Pandas a database connection, such as the one in the previous example, or an SQLAlchemy connection. We will cover the latter in the later sections of this chapter. We will load the statsmodels sunactivity data, just as we did in the previous chapter, Chapter 7, Signal Processing and Time Series:

  1. Create a list of tuples to form the Pandas DataFrame:

            rows = [tuple(x) for x in df.values] 
    

    Contrary to the previous example, create a table without specifying data types:

                con.execute("CREATE TABLE sunspots(year, sunactivity)") 
    
  2. The executemany() method executes multiple statements; in this case, we will be inserting records from a list of tuples. Insert all the rows into the table and show the row count as follows:

            con.executemany("INSERT INTO sunspots(year, sunactivity) VALUES 
            (?, ?)", rows) 
            c.execute("SELECT COUNT(*) FROM sunspots") 
            print(c.fetchone()) 
    

    The number of rows in the table is printed as follows...