Python3.4.3/C2/Subplots/English
 Python/C2/Subplots/English
Title of script: Subplots
Author: Aditya Palaparthy
Keywords: Python, IPython, plot, subplot


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containing title, name of the production team along with the logo of MHRD 
Hello Friends. Welcome to the spoken tutorial on "Subplots".

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Objectives 
At the end of this tutorial, you will be able to create and switch between subplots. 
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System Specifications 
To record this tutorial, I am using

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Prerequisites 
To practise this tutorial, you should know how to
If not, see the prerequisite Python tutorials on this website. 
[Terminal]
ipython3 
Let us first open the Terminal by pressing Ctrl+Alt+T keys simultaneously.

[IPython console]
percentage pylab and press Enter. 
Let us initialise the pylab package.

[IPython Terminal] x = linspace(0, 50, 500) plot(x, cos(x)) y = linspace(0, 5, 100) plot(y, y ** 2) 
To compare two plots we draw the plots in the same plotting area.
x equals to linspace inside brackets 0 comma 50 comma 500 and press Enter. plot inside brackets x comma cos(x)
y equals to linspace inside brackets 0 comma 5 comma 100.
plot inside brackets y comma y square. 
[Plot Window] 
Here the two plots have different regular axes. So we cannot draw overlaid plots. 
[IPython Terminal]
subplot(2, 1, 1) 
In such cases we can draw subplots. We use subplot command to accomplish this.
clf() subplot inside the brackets 2 comma 1 comma 1 
[Plot Window]  We can see the first subplot. 
Pause for a while and highlight  The subplot command takes three arguments.
Here the first argument is 2, to split the plot horizontally. 
Pause for a while and highlight  The second argument is the number of columns of subplots that must be created.
Here the second argument is 1. So plot will not split vertically. 
Pause for a while and highlight  The last argument specifies the serial number for the subplot.
Here we passed 1 as the argument, which creates the upper subplot 
[IPython Terminal]

If we execute the subplot command as
the lower subplot is created. 
[Plot Window]  Here, we can see two subplots. 
[IPython Terminal]
x = linspace(0, 50, 500) subplot(2, 1, 1) plot(x, cos(x)) y = linspace(0, 5, 100) subplot(2, 1, 2) plot(y, y ** 2)

Now we can draw plots in each of the subplot area using the plot command.
Type subplot inside brackets 2 comma 1 comma 1 plot inside brackets x comma cos(x)
subplot inside brackets 2 comma 1 comma 2 plot y comma y square 
[Plot window]  This created two plots one in each of the subplot area.

[Plot window]  It is clear from the two subplots that both have different regular axes. 
[Plot window]  For the cosine curve, xaxis varies from 0 to 50 and yaxis varies from minus 1 to 1. 
[Plot window]  For the parabolic curve, xaxis varies from 0 to 5 and yaxis varies from 0 to 25. 
[IPython Terminal]
clf() 
Now clear the plot window 
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Exercise 1

Pause the video. Try this exercise and then resume the video

Switch to the terminal for the solution.  
[IPython Terminal]
v = linspace(21, 100, 500) 
To start with, we have been given the range of Volume from which we can define the variable v.
v equals to linspace inside brackets 21 comma 100 comma 500 
[IPython Terminal]
subplot(2, 1, 1) plot(v, 2.0/v) 
We can create first subplot and draw Pressure v/s Volume graph using this v.
We know that nRT is a constant which is equal to 2.0 since

[IPython Terminal]
subplot(2, 1, 2) plot(200, 2.0/v) 
Now we can create the second subplot and draw the Pressure v/s Temperature plot as follows

[IPython Terminal]
t = linspace(200, 200, 500) 
We have an error now, telling x and y dimensions don't match.
So we will create same number of points for temperature.
t equals to linspace inside brackets 200 comma 200 comma 500. 
[IPython Terminal]

Now, we have 500 values in t and each with the value 200 Kelvin.
Plotting this data, we get the required plot.
plot inside brackets t comma 2 point 0 divided by v 
[Plot Window]  We can see two subplots of Pressure v/s Volume and Pressure v/s Temperature respectively. 
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Summary slide 
This brings us to the end of this tutorial.

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Evaluation

Here are some self assessment questions for you to solve.

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Solutions 
And the answer is first option.

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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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Acknowledgement 
Spokentutorial is funded by NMEICT, MHRD, Govt. of India.
For more details, visit this website. 
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Thank You 
This is Usha from IIT Bombay signing off.
Thank You. 