Difference between revisions of "Python-3.4.3/C2/Other-Types-Of-Plots/English"

Learning Objectives

• Create scatter plot
• Create log-log plots

• Create scatter plot
• Create log-log plots

System Specifications

• Ubuntu Linux 14.04 operating system
• Python 3.4.3
• IPython 5.1.0

Pre-requisites

• run basic Python commands on the ipython console
• Load data from files and
• Plot data.

If not, see the relevant Python tutorials on http://spoken-tutorial.org

• run basic Python commands on the ipython console
• Load data from files and
• Plot data.

If not, see the relevant Python tutorials on this website.

ipython3

Now, type ipython3 and press Enter.

%pylab and press Enter.

Type percent pylab and press Enter.

Scatter plot

Each point determines its position on the x and y axes

Exercise 1

• Plot a scatter plot showing the percentage profit of a company A from the year 2000 to 2010.

• The data for the same is available in the file company hyphen a hyphen data dot txt.

• company hyphen a hyphen data dot txt file is available in the code file link of this tutorial.

• Please download and use it.

cat company-a-data.txt

So type,

cat company hyphen a hyphen data dot txt. and press Enter

The first column represents the years. And the second column represents the profit percentage.

year, profit = loadtxt('company-a-data.txt', unpack = True)

we first need to load the data from the file using loadtxt command.

Type

year comma profit equal to loadtxt within parentheses within single quotes company hyphen a hyphen data dot txt after single quotes comma unpack equal to True and Press Enter

scatter() function

Syntax: scatter within parentheses x comma y

• x is a sequence of data
• y is a sequence of data having the same length of x

scatter(year, profit)

Type scatter within parentheses year comma profit and press Enter.

Notice that we passed two arguments to scatter() function.

First one being the values in x-coordinate that is year.

Second, the values in y-coordinate, the profit percentages.

Exercise

Read the documentation of scatter.

Plot a scatter plot of same data in company hyphen a hyphen data dot txt with red diamond markers.

clf()

scatter(year,profit,color='r',marker='d')

Clear the plot window by typing clf parentheses and press Enter

Now type

scatter within parentheses year comma profit comma color equal to within single quotes r comma marker equal to within single quotes d and press Enter

Now let us see another kind of plot.

log-log graph

• A log-log plot is a two-dimensional graph of numerical data.
• It uses logarithmic scales on both axes.
• Graph appears as straight line due to non-linear scaling

loglog() function

loglog within parentheses x comma y

• x is a sequence of data
• y is a sequence of data, having the same length of x

Exercise 3

x = linspace(1,20,100)

y = 5*x**3

Type

x equalto linspace within parentheses 1 comma 20 comma 100 and press Enter

Then, y equal to 5 into x raised to 3 and press Enter

clf()

loglog(x,y)

Type loglog within parentheses x comma y and press Enter

Summary

1. Plot a scatter plot using scatter() function

1. Plot a log-log graph using loglog() function

Assignment

1. scatter within parentheses x comma y comma color equal to within single quotes blue comma marker equal to within single quotes d

and plot within parentheses x comma y comma color equal to within single quotes b comma marker equal to within single quotes d does exactly the same.?

• True or False

Solution to assignment

1. False. Both functions do not produce the same kind of plot.

Forum

Fossee Forum

Textbook Companion

Acknowledgment

http://spoken-tutorial.org

For more details, visit this website.

Thank you.