Python-3.4.3/C2/Plotting-Charts/English
Title of script: Plotting Charts
Author: Trupti Kini, Thirumalesh H S
Keywords: Python, IPython, pylab, scatter plot, charts, matplotlib help
Visual Cue | Narration |
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Hello friends. Welcome to the tutorial on plotting charts |
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Learning Objectives |
At the end of this tutorial, you will be able to -
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System Specifications |
To record this tutorial, I am using
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Pre-requisites |
To practice this tutorial, you should know how to
If not, see the relevant Python tutorials on this website. |
Open [Terminal] and type
ipython3
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Let us first open the Terminal by pressing Ctrl+Alt+T keys simultaneously.
Now, type ipython3 and press Enter. |
[IPython console]
type %pylab and press Enter. |
Let us initialize the pylab package.
Type %pylab and press Enter. |
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Pie chart |
A pie chart is a circular chart divided into sectors, to illustrate numerical proportion |
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pie() function Syntax: pie(values, labels= labels)
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The syntax for pie() function is as follows:
pie inside parentheses values comma labels equal to labels
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Exercise 1 |
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[File browser]
Open the file company-a-data.txt and show the content |
The data file has two columns with a set of values in each column.
The first column represents years. The second column represents the profit percentages. |
[IPython Terminal]
year, profit = loadtxt('company-a-data.txt', unpack = True) |
To produce a scatter plot, we first need to load the data from the file using loadtxt command.
Let us clear the terminal. Type year comma profit equal to loadtxt inside parentheses inside single quotes add the path of the file company-a-data.txt comma unpack equal to True and press Enter unpack equal to True --> returns the transposed array of data. |
[Ipython Terminal]
clf() pie(profit,labels=year) |
Type clf open and close parentheses to clear the plot window, if any plots executed previously.
Type pie(profit comma labels equal to year) and press Enter. |
[Plot Window]
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Notice that we passed two arguments to the function pie().
First one being the values, which is profit in our case. The next one being the set of labels to be used in the pie chart, which is year in our case. |
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Exercise 2 |
Pause the video here.
Try out the following exercise and resume the video.
Hint: In your ipython interpreter, try typing pie question mark. |
[IPython Terminal]
clf() pie(profit,labels=year,colors=('w','r','k','m','y','b','g','c','y','m','b')) |
Solution to Exercise 2
Clear the plot window by typing clf open and close parentheses and press Enter. Type pie inside parentheses profit comma labels equal to year comma colors equal to inside parentheses the color codes and press Enter. This will display a pie chart with each wedge having the color as specified in the parameters. |
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Bar chart |
A bar chart is a chart
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bar() function |
The syntax for bar chart is:
bar inside parentheses x comma y
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Exercise 3 |
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[IPython Terminal]
bar(year, profit) |
Solution to Exercise 3
Clear the plot window by typing clf open and close parentheses Type bar open and close parentheses year comma profit and press Enter. This will display a bar chart representing the profit percentage of company A |
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Exercise 4 |
Plot a bar chart as shown in the image:
Hint: Bar chart is not filled and which is hatched with 45o slanting lines. The data for the chart may be obtained from the file company-a-data.txt. Hint: In your ipython interpreter, try typing bar question mark
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[Ipython Terminal]
clf() bar(year,profit,fill=False,hatch='/') |
Solution to Exercise 4
Clear the plot window by typing clf open and close parentheses Type bar open and close parentheses year comma profit comma fill equal to False comma hatch equal to inside single quotes slanting line and press Enter. This will display a bar chart which is not filled and which is hatched with 45o slanting lines |
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"Getting help on matplotlib" {SHOW WEBSITE while narrating} matplotlib.sourceforge.net/users/screenshots.html and also at matplotlib.sourceforge.net/gallery.html |
Help about matplotlib can be obtained from matplotlib.sourceforge.net/contents.html
More plots can be seen at the following links |
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Summary slide |
This brings us to the end of this tutorial.
In this tutorial we learnt to,
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Assignment
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Here are some self assessment questions for you to solve.
1.What statement can be issued to generate a bar chart with vertical line hatching?
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Solution to assignment |
And the answer is,
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Forum |
Please post your timed queries in this forum. |
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Fossee Forum |
Please post your general queries on Python in this forum. |
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Textbook Companion |
FOSSEE team coordinates the TBC project. |
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Acknowledgment |
Spoken Tutorial Project is funded by NMEICT, MHRD, Govt. of India.
For more details, visit this website. |
Previous slide | This is Trupti Kini from FOSSEE IIT Bombay signing off.
Thank you. |