Book Image

NumPy: Beginner's Guide

By : Ivan Idris
Book Image

NumPy: Beginner's Guide

By: Ivan Idris

Overview of this book

Table of Contents (21 chapters)
NumPy Beginner's Guide Third Edition
About the Author
About the Reviewers
NumPy Functions' References

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

    The histogram for DISH appears as follows:

What just happened?

We charted the stock price distribution of DISH as a histogram (see

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

today =
start = (today.year - 1, today.month,

symbol = 'DISH'

if len(sys.argv) == 2:
   symbol = sys.argv[1]

quotes = quotes_historical_yahoo...