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
Show slide	Hello friends. Welcome to the tutorial on plotting Narrator name is missing in the first slide charts
Show slide Learning Objectives	At the end of this tutorial, you will be able to - Create pie charts Create bar charts and Find more information on matplotlib
Show slide System Specifications	To record this tutorial, I am using Ubuntu Linux 14.04 operating system Python 3.4.3 IPython 5.1.0
Show slide Pre-requisites	To practice this tutorial, you should know how to 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.
[Terminal] ipython3	Let us first open the Terminal by pressing Ctrl+Alt+T keys simultaneously. Now, type ipython3 and press Enter.
[IPython console] %pylab and press Enter.	Let us initialise the pylab package. Type %pylab and press Enter.
Show Slide Pie chart	A pie chart is a circular chart divided into sectors, change the text in slide to illustrate numerical proportion
Show Slide pie() function Syntax: pie(values, labels= labels) values – the data to be plotted labels – the label for each wedge in the pie chart	The syntax for pie() function is as follows: pie(values, labels= labels) values – the data to be plotted labels – the label for each wedge in the pie chart
Show Slide Exercise 1	Plot a pie chart representing the profit percentage of company A. Use the data from file company-a-data.txt available in the code file link of this tutorial
[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 line 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. Type year, profit = loadtxt('add/path/company-a-data.txt', unpack = True) unpack = True --> returns the transposed array of data
[Ipython Terminal] clf() pie(profit,labels=year)	Type clf() to clear the plot window, if any plots executed previously. Type pie(profit,labels=year)
[Plot Window] Show pie chart plot	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.
Show Slide Exercise 2	Pause the video here, try out the following exercise and resume the video. Plot a pie chart with the same data with the following colors for each wedges. white, red, black, magenta, yellow, blue, green, cyan, yellow, magenta and blue. Hint: In your ipython interpreter, try typing pie?
[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() Type pie(profit,labels=year,colors=('w','r','k','m','y','b','g','c','y','m','b')) This will display a pie chart with each wedge having the color as specified in the parameters.
Show Slide Bar chart	A bar chart is a chart with rectangular bars with lengths proportional to the values that they represent.
Show Slide bar() function	The syntax for bar graph is: bar(x, y) x – a sequence of data y - a sequence of data, the same length of x
Show Slide Exercise 3	Plot a bar chart representing the profit percentage of company A. Use the data from file company-a-data.txt.
[IPython Terminal] clf() bar(year, profit)	Solution to Exercise 3 Clear the plot window by typing clf() Type bar(year, profit) This will display a bar chart representing the profit percentage of company A
Show Slide 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? Clue is to try typing bar? In ipython interpreter.
[Ipython Terminal] clf() bar(year,profit,fill=False,hatch='/')	Solution to Exercise 4 Clear the plot window by typing clf() Type bar(year,profit,fill=False,hatch='/') This will display a bar chart which is not filled and which is hatched with 45o slanting lines
Show Slide "Getting help on matplotlib" {SHOW WEBSITE while narrating}	Help about matplotlib can be obtained from matplotlib.sourceforge.net/contents.html More plots can be seen at matplotlib.sourceforge.net/users/screenshots.html and also at matplotlib.sourceforge.net/gallery.html
Show Slide Summary slide	This brings us to the end of this tutorial. In this tutorial we learnt to, Plot a pie chart using pie() function Plot a bar chart using bar() function Access the matplotlib online help
Show Slide Assignment	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? bar(x, y, color='w', hatch='/') bar(x, y, fill=False, hatch='//') bar(x, y, fill=False, hatch='|') bar(x, y, color='w', hatch='\')
Show Slide Solution to assignment	And the answers, bar(x, y, fill=False, hatch='|') is the correct option to generate a bar chart with vertical line hatching.
Show Slide Forum	Please post your timed queries in this forum.
Show Slide Fossee Forum	Please post your general queries on Python in this forum.
Show Slide Textbook Companion	FOSSEE team coordinates the TBC project.
Show Slide Acknowledgment http://spoken-tutorial.org	Spoken Tutorial Project is funded by NMEICT, MHRD, Govt. of India. For more details, visit this website.
Previous slide	This is _________ from IIT Bombay (or FOSSEE, if you wish) signing off. Thank you.

Contributors and Content Editors

Nancyvarkey, Nirmala Venkat, Trupti