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Numpy Beginner's Guide (Update)

You're reading from   Numpy Beginner's Guide (Update) Build efficient, high-speed programs using the high-performance NumPy mathematical library

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Product type Paperback
Published in Jun 2015
Publisher
ISBN-13 9781785281969
Length 348 pages
Edition 1st Edition
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Author (1):
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Ivan Idris Ivan Idris
Author Profile Icon Ivan Idris
Ivan Idris
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Toc

Table of Contents (16) Chapters Close

Preface 1. NumPy Quick Start 2. Beginning with NumPy Fundamentals FREE CHAPTER 3. Getting Familiar with Commonly Used Functions 4. Convenience Functions for Your Convenience 5. Working with Matrices and ufuncs 6. Moving Further with NumPy Modules 7. Peeking into Special Routines 8. Assuring Quality with Testing 9. Plotting with matplotlib 10. When NumPy Is Not Enough – SciPy and Beyond 11. Playing with Pygame A. Pop Quiz Answers B. Additional Online Resources C. NumPy Functions' References
Index

Time for action – charting stock price distributions

Let's chart the stock price distribution of quotes from Yahoo Finance.

  1. Download the data going back one year:
    today = date.today()
    start = (today.year - 1, today.month, today.day)
    
    quotes = quotes_historical_yahoo(symbol, start, today)
  2. The quotes data in the previous step is stored in a Python list. Convert this to a NumPy array and extract the close prices:
    quotes = np.array(quotes)
    close = quotes.T[4]
  3. Draw the histogram with a reasonable number of bars:
    plt.hist(close, np.sqrt(len(close)))
    plt.show()

    The histogram for DISH appears as follows:

    Time for action – charting stock price distributions

What just happened?

We charted the stock price distribution of DISH as a histogram (see stockhistogram.py):

from matplotlib.finance import quotes_historical_yahoo
import sys
from datetime import date
import matplotlib.pyplot as plt
import numpy as np

today = date.today()
start = (today.year - 1, today.month, today.day)

symbol = 'DISH'

if len(sys.argv) == 2:
   symbol = sys.argv...
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