Difference between revisions of "Python/C2/Additional-features-of-IPython/English-timed"
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Revision as of 12:30, 10 July 2014
| Time | Narration |
| 00:00 | Hello friends and welcome to the tutorial on "Additional Features of IPython". |
| 00:06 | At the end of this tutorial, you will be able to,
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| 00:19 | Before beginning this tutorial,we would suggest you to complete the tutorial on "Embellishing a plot". |
| 00:24 | Let us start ipython with pylab loaded, by typing ipython space hyphen pylab on the terminal. |
| 00:33 | We shall first make a plot and then view the history and save it, for that we can type x = linspace within brackets minus 2 into pi comma 2 into pi comma 100
plot within bracket x comma xsinx cosx and hit enter
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| 01:00 | We got an error saying "xsinx is not defined". |
| 01:04 | This is because xsin(x) is actually x star sin(x), for that we have to type on the terminal
plot within bracket x comma x star sin(x) plot x, sin(x) xlabel within bracket in double quotes x then ylabel within bracket in double quotes dollar sign f(x) again a dollar sign then title within bracket in double quotes x and xsin(x) then again title within bracket in double quotes dollar sign x and xsin(x) and again a dollar sign
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| 02:15 | We now have the plot. |
| 02:18 | Let us look at the commands that we have typed in. |
| 02:21 | The history can be retrieved by using modulo hist command. |
| 02:28 | Type modulo that is percentage sign then hist and hit enter |
| 02:37 | As you can see, it displays a list of recent commands that we typed. |
| 02:41 | Every command has a number in front, to specify in which order and when it was typed. |
| 02:48 | So, Please note that there is a percentage sign before the hist command. |
| 02:52 | This implies that percentage hist is a command that is specific to IPython only and not to any other version of python. |
| 03:00 | These other type of commands are called as magic commands. |
| 03:04 | Also note that, the %hist itself is a command and is displayed as the most recent command. |
| 03:15 | We should note that anything we type in is stored as history, irrespective of whether it is command or an error or IPython magic command. |
| 03:27 | If we want only the recent 5 commands to be displayed, we pass the number as an argument to percentage hist command. |
| 03:35 | Hence percentage hist 5 displays the recent 5 commands, inclusive of the percentage hist command that we gave. |
| 03:46 | The default number is 40. |
| 03:48 | So to try this we can type in the terminal percentage hist space 5 and hit enter. |
| 03:58 | Pause the video here, try out the following exercise and resume the video. |
| 04:02 | Read through the documentation of %hist and find out how to list all the commands between 5 and 10. |
| 04:11 | As we can see from percentage hist documentation,percentage hist 5 space 10 displays the commands from 5 to 10 |
| 04:22 | Now that we have the history, we will try it on the command prompt, so you can type percentage hist 5 space 10 and hit enter. |
| 04:35 | we would like to save the required line of code from history. |
| 04:39 | So, This is possible by using the percentage save command. |
| 04:47 | So, Before we do that, let us first look at history and identify what lines of code we require. So type percentage hist on the terminal and hit enter. |
| 04:58 | The first command is linspace. |
| 05:00 | But second command is a command that gave us an error. |
| 05:06 | Hence we do not need second command. |
| 05:09 | The commands from third to sixth are required. |
| 05:12 | The seventh command although is correct, we do not need it since we are setting the title correctly in the eighth command. |
| 05:20 | So we need first third to sixth and the eighth command for our program. |
| 05:26 | Hence you can type in the syntax of percentage save slash home slash fossee slash plot underscore script dot py space 1 space 3 hyphen 6 space 8 |
| 05:46 | This command saves the first line of code and then third to sixth followed by the eighth lines of code into the specified file. |
| 05:55 | The first argument to percentage save is the path of file and save the commands and the arguments there after are the commands to be saved in the given order. |
| 06:08 | Pause the video here, try out the following exercise and resume the video. |
| 06:11 | Change the label on y-axis to "y" and save the lines of code accordingly. |
| 06:17 | we use the command ylabel on interpreter |
| 06:21 | So you can type, ylabel within brackets in double quotes y and hit enter |
| 06:29 | and then you can do percentage save command |
| 06:36 | That is you can type percentage save then slash home slash fossee slash example underscore plot dot py then 1 space 3 hyphen 6 space 10 |
| 06:51 | Now that we have the required lines of code in a file, let us learn how to run the file as a python script. |
| 06:58 | We use the IPython magic command percentage run to do this. |
| 07:03 | So Type percentage run space hyphen i space slash home slash fossee slash plot underscore script dot py |
| 07:18 | The script runs but we do not see the plot. This happens because when we are running a script, we are not in the interactive mode anymore. |
| 07:27 | Hence to view the plot, you have to type, show and then brackets on your terminal |
| 07:38 | So now Pause the video here, try out the following exercise |
| 07:41 | Use percentage hist and percentage save and create a script that has the function show() in it. |
| 07:49 | Run the script to produce the plot and display the name. |
| 07:56 | So you can type percentage hist space 20 on the terminal |
| 08:06 | We first look at the history using this command only, |
| 08:09 | Then save the script using the command percentage save slash home slash fossee slash show underscore included dot py space 1 space 3 hyphen 6 then space 8 then 14 and 17 |
| 08:37 | then on the next line you can type
percentage run hyphen i slash home slash fossee slash show underscore included dot py, then type show, show function to get the plot. |
| 09:03 | We get the desired plot now. |
| 09:07 | The reason for including a hyphen i after run is to tell the interpreter that if any name is not found in script, search for it in the interpreter. |
| 09:17 | Hence all these sin, plot, pi and show which are not available in script, are taken from the interpreter and used to run the script. |
| 09:32 | So now, Pause the video here, try out the following exercise and resume the video. |
| 09:36 | Run the script without using the hyphen i option. |
| 09:42 | So Do you find any difference? |
| 09:47 | So you can type percentage run slash home slash fossee slash included hypen included dot py |
| 10:04 | We see that it raises Name Error saying that the name linspace is not found. |
| 10:12 | This brings us to the end of this tutorial. |
| 10:14 | In this tutorial,we have learnt to, Retrieve the history using percentage hist command. |
| 10:21 | then View only a part of history by passing an argument to 'percentage hist' command. |
| 10:25 | then Save the required lines of code in required order using 'percentage save' command. |
| 10:30 | then Use 'percentage run hyphen i' command to run the saved script. |
| 10;39 | Here are some self assessment questions for you to solve |
| 10:43 | 5. How do you retrieve the recent 5 commands |
| 10:46 | And there are four options percentage hist,percentage hist minus 5,percentage hist 5,percentage hist 5 to 10 |
| 10:57 | And in second, How do you save the lines 2 3 4 5 7 9 10 11 and the options are percentage save filepath 2 hyphen 5 7 9 hyphen 11,then percentage save filepath 2 hyphen 11,then percentage save filepath then after that percentage save 2 hyphen 5 7 9 10 11 |
| 11:24 | And the final question is What will the command percentage hist 5 space 10 display. |
| 11:30 | The recently typed commands from 5 to 10 inclusive of the history command |
| 11:34 | The recently typed commands from 5 to 10 excluding the history command |
| 11:38 | So now the answers, |
| 11:41 | In order to retrieve the recently typed 5 commands,we have to say percentage hist 5 for the first question. |
| 11:49 | So second question answer is percentage save file path 2 hyphen 5 space 7 space 9 hyphen 11 is the correct option to the specified lines of codes. |
| 12:02 | And Then third answer is percentage hist 5 space 10 will display the recently typed commands from 5 to 10 inclusive of the history command. |
| 12:14 | This brings us to the end of this tutorial |
| 12:17 | So we Hope you have enjoyed and found it useful.Thank you. |
