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Python Data Analysis, Second Edition

Python Data Analysis, Second Edition

By : Idris
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Python Data Analysis, Second Edition

Python Data Analysis, Second Edition

4 (4)
By: 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 (16 chapters)
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13
A. Key Concepts
15
C. Online Resources

Fancy indexing


Fancy indexing is indexing that does not involve integers or slices, which is conventional indexing. In this tutorial, we will practice fancy indexing to set the diagonal values of the Lena photo to 0. This will draw black lines along the diagonals, crossing through them.

The following is the code for this example:

import scipy.misc 
import matplotlib.pyplot as plt 
 
face = scipy.misc.face() 
xmax = face.shape[0] 
ymax = face.shape[1] 
face=face[:min(xmax,ymax),:min(xmax,ymax)] 
xmax = face.shape[0] 
ymax = face.shape[1] 
face[range(xmax), range(ymax)] = 0 
face[range(xmax-1,-1,-1), range(ymax)] = 0 
plt.imshow(face) 
plt.show() 

The following is a brief explanation of the preceding code:

  1. Set the values of the first diagonal to 0.

    To set the diagonal values to 0, we need to specify two different ranges for the x and y values (coordinates in a Cartesian coordinate system):

            face[range(xmax), range(ymax)] =...

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