Python-3.4.3/C2/Additional-features-of-IPython/English

Additional-features-of-IPython - English

Title: Additional-features-of-IPython – English

Author: Usha Viswanathan, Thirumalesh H S

Keywords: Video tutorial, IPython, running script, saving script,

Visual Cue	Narration
Show Slide containing title, name of the production team along with the logo of MHRD	Hello friends and welcome to the Spoken Tutorial on Additional Features of IPython.
Show Slide Objectives	At the end of this tutorial, you will be able to, Retrieve your IPython history. View a part of the history. Save a part of a history to a file. Run a script from within IPython.
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 use Plots interactively and embellish a plot If not, see the pre-requisite Python tutorials on this website.
[Terminal] ipython3	Let us now 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 percentage pylab and press Enter
[IPython Terminal] x = linspace(-2*pi, 2*pi, 100) press Enter	To start plotting, type x equals to linspace inside the brackets minus 2pi comma 2pi comma 100 then press Enter.
[IPython Terminal] plot(x, xsin(x)) press Enter	Next type plot inside the brackets x comma xsin(x) and then press Enter
Highlight the message “xsin is not defined” on the terminal.	We got an error saying "xsin is not defined". This is because xsin(x) is actually x multiplied by sin(x)
[IPython Terminal] plot(x, x*sin(x)) Press Enter	Here, multiplication sign is missing. So let us type plot inside the brackets x comma x multiplied by sin(x) and press Enter.
[IPython Terminal] Type xlabel("$x$") ylabel("$f(x)$") title("$x and xsin(x)$")	Next let us add title and the labels for both x and y axes. Type xlabel inside the brackets inside inverted commas inside dollar sign x press Enter. ylabel inside the brackets inside inverted commas inside dollar sign f(x) Title inside the brackets inside 'inverted commas inside dollar sign x and xsin(x) We can now see the labelled plot.
[IPython Terminal] Type %history and press Enter	The history of typed commands can be retrieved by percentage history command. Type percentage history and press Enter.
	percentage history itself is a command and is displayed as the most recent command. Whatever we executed in the terminal is stored as history.
[IPython Terminal] Type %history 5 and press Enter	If we want to see what was the fifth command, pass 5 as an argument to percentage history command. Type percentage history space 5 and press Enter. This displays the fifth command which we typed.
Show Slide Assignment 1	Now pause the video here, try out the following exercise and resume the video. Find out how to list the recent commands between 5 and 10.
	Switch back to terminal.
[IPython terminal] In examples of history doc, highlight Example >> %history -n 4-6 Now quit history doc and type %history 5-10 and press Enter	Let us look at the solution. Type clf() Type percentage history question mark Read through the information of percentage history command. We can see, percentage history hypen n 4 hypen 6 displays the commands from 4 to 6. Here hypen n is an optional argument which prints line numbers. Type q to quit the documentation Now type percentage history space 5 hypen 10 and press Enter.
	To save the history, we use percentage save command.
[IPython Terminal] Type %history and press Enter	Before we do that, let us first look at the history and identify which lines of code we require. Type percentage history and press Enter.
[IPython Terminal] Highlight the commands on the terminal.	The second command is linspace. But the third command is a command that gave us an error. Hence we do not need it. The commands from fourth to seventh are required.
[IPython Terminal] Type %save plot_script.py 2 4-7 and press Enter	So we need the second command and then the fourth to seventh commands for our program. Let us save it in the present working directory. Hence the syntax will be percentage save space plot underscore script.py space 2 space 4 hypen 7. press Enter
[IPython Terminal] Highlight the typed command on the terminal.	The first argument in percentage save command is the name of the file in which the commands are saved. The second argument gives the numbers of the commands that are being saved separated by spaces.
[File Browser] Goto file plot_script.py. open and show it	Let us now open the file plot underscore script.py and see the contents.
[IPython Terminal] Type %run -i plot_script.py and press Enter	Let us learn how to run the file as a python script. We use the command percentage run to do this. Type percentage run space hypen i space plot underscore script.py and press Enter. Here, hypen i parameter runs the code written in a text editor. The code is run within the current ipython session. It uses the variables defined interactively in the ipython session.
[IPython Terminal] Type show() and press Enter	The script runs but we do not see the plot. This is because when we are running a script, we are not in the interactive mode. To view the plot, type show() on your terminal. Press Enter.
Show Slide Assignment 2	Pause the video here, try out the following exercise and resume the video. Use percentage history and percentage save to create a script that has the function show() in it. Run the script to produce the plot and display the same.
[IPython Terminal] %history -n press Enter	Let us look at the solution. We first look at the history using percentage history hypen n command. Type percentage history space hypen n and press Enter.
[IPython Terminal] Type clf() press Enter	Let us clear the plot window Type clf() and press Enter
[IPython Terminal] Type %save show_included.py 1 3-7 12 15 Press Enter	Now let us save the script using the command percentage save We need lines 2, 4 to 7 and 16 Type percentage save space show underscore included.py space 2 space 4 hypen 7 space 16 and press Enter
[IPython Terminal] Type %run -i show_included.py Press Enter	To run the script type percentage run space hypen i space show underscore included.py Then press Enter
	We get the desired plot.
[IPython Terminal] Go to the previous command. Modify it by removing ‘-i’ in the command to, %run show_included.py and Press Enter	Go to the previous command. Modify it by removing ‘hypen i’ in the command to, percentage run space show underscore included.py We see that it raises a NameError saying that the name linspace is not defined. This happens because we did not run the script interactively.
Show Slide Summary	This brings us to the end of this tutorial. In this tutorial,we have learnt to, 1. Retrieve the history using percentage history command. 2. View only a part of history by passing argument to percentage history command.
Show Slide Summary	3. Save the required lines of code in required order using percentage save command. 4. Use 'percentage run space hypen i' command to run a saved script.
Show Slide Self assessment 1	How do you save the command lines 2 3 4 5 7 9 10 11? percentage save <filename> 2-5 7 9 hyphen 11 percentage save <filename> 2 hyphen 11 percentage save <filename> percentage save 2 hyphen 5 7 9 hyphen 11
Show Slide Self assessment 2	Which is the command to run the script? Percentage execute <script name> percentage run hyphen i <script name> percentage run <script name> percentage execute hyphen i <script name>
Show Slide And the solutions are	And the answers, To save the commands 2 3 4 5 7 9 10 11, we issue the command percentage save <filename> 2 hyphen 5 space 7 space 9 hyphen 11 To run the script we use percentage run space hyphen i <scriptname>
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 Usha from IIT Bombay (or FOSSEE, if you wish) signing off. Thank you.

Contributors and Content Editors

Nancyvarkey, Nirmala Venkat, Vineeta