Book Image

NumPy Cookbook - Second Edition

By : Ivan Idris
Book Image

NumPy Cookbook - Second Edition

By: Ivan Idris

Overview of this book

<p>NumPy has the ability to give you speed and high productivity. High performance calculations can be done easily with clean and efficient code, and it allows you to execute complex algebraic and mathematical computations in no time.</p> <p>This book will give you a solid foundation in NumPy arrays and universal functions. Starting with the installation and configuration of IPython, you'll learn about advanced indexing and array concepts along with commonly used yet effective functions. You will then cover practical concepts such as image processing, special arrays, and universal functions. You will also learn about plotting with Matplotlib and the related SciPy project with the help of examples. At the end of the book, you will study how to explore atmospheric pressure and its related techniques. By the time you finish this book, you'll be able to write clean and fast code with NumPy.</p>
Table of Contents (19 chapters)
NumPy Cookbook Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Exploring atmospheric pressure


In this recipe, we will take a look at the daily mean sea level pressure (in 0.1 hPa) calculated from 24 hourly values. This includes printing descriptive statistics and visualizing the probability distribution. In nature, we often deal with the normal distribution, so the normality test from Chapter 10, Fun with Scikits, will come in handy.

The complete code is in the exploring.py file in this book's code bundle:

from __future__ import print_function
import numpy as np
import matplotlib.pyplot as plt
from statsmodels.stats.adnorm import normal_ad

data = np.load('cbk12.npy')

# Multiply to get hPa values
meanp = .1 * data[:,1]

# Filter out 0 values
meanp = meanp[ meanp > 0]

# Get descriptive statistics
print("Max", meanp.max())
print("Min", meanp.min())
mean = meanp.mean()
print("Mean", mean)
print("Median", np.median(meanp))
std = meanp.std()
print("Std dev", std)

# Check for normality
print("Normality", normal_ad(meanp))

#histogram with Gaussian PDF...