Difference between revisions of "Python/C2/Getting-started-with-ipython/English-timed"
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| − | | Hello | + | | Hello friends and welcome to the tutorial on '''Getting started with ipython'''. |
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| 00:07 | | 00:07 | ||
| − | | At the end of this tutorial, you will be able to | + | | At the end of this tutorial, you will be able to: |
| − | + | # invoke the '''ipython interpreter''' . | |
| − | # invoke the ipython interpreter . | + | |
# quit the ipython interpreter. | # quit the ipython interpreter. | ||
| − | # navigate the ipython session history. | + | # navigate the ipython session '''history'''. |
| − | # use tab-completion for writing ipython | + | # use tab-completion for writing '''ipython function'''s. |
# look-up documentation of functions. | # look-up documentation of functions. | ||
# interrupt incomplete or incorrect commands. | # interrupt incomplete or incorrect commands. | ||
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| 00:27 | | 00:27 | ||
| − | | | + | | '''iPython''' is an enhanced '''Python interpreter''' that provides features like tab-completion, easier access to '''help''' and many other functionalities. |
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| 00:37 | | 00:37 | ||
| − | |Let us first see how to start the ipython interpreter. | + | |Let us first see how to start the '''ipython interpreter'''. |
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| 00:41 | | 00:41 | ||
| − | | First open the terminal | + | | First, open the terminal. Type: "ipython" in the terminal and hit '''Enter'''. |
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| 00:51 | | 00:51 | ||
| − | | After getting some information about the version of Python installed and some help commands, we get a prompt with In[1]:. | + | | After getting some information about the version of Python installed and some help commands, we get a prompt with '''In[1]:'''. |
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| 01:09 | | 01:09 | ||
| − | | Now, | + | | Now, let's see how we can quit the 'ipython interpreter'. Press '''Ctrl, D'''. |
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| 01:17 | | 01:17 | ||
| − | | A prompt will appear to confirm whether you really want to exit | + | | A prompt will appear to confirm whether you really want to exit; type 'y' to say 'yes' and quit 'ipython' and 'n' to say 'no' if you don't want to quit the ipython. |
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| 01:28 | | 01:28 | ||
| − | | Press y. | + | | Press 'y'. |
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| 01:32 | | 01:32 | ||
| − | | Now since we have quit the | + | | Now, since we have quit the interpreter, let us start it again by typing "ipython". |
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| 01:48 | | 01:48 | ||
| − | |type ''1+2 ''at the prompt. | + | |type: '''1+2'''at the prompt. |
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| 01:55 | | 01:55 | ||
| − | | | + | |'''iPython''' promptly gives back the output as ''3''. |
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| 01:59 | | 01:59 | ||
| − | |Notice that the output is displayed with an Out[1] indication. | + | |Notice that the output is displayed with an '''Out[1]''' indication. |
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| 02:05 | | 02:05 | ||
| − | | Now, | + | | Now, let us try few more operations such as- '''5 minus 3, 7 minus 4, 6 into 5'''. |
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| 02:23 | | 02:23 | ||
| − | | Now let's see how the ipython remembers the history of commands. | + | | Now, let's see how the ipython remembers the '''history''' of commands. |
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| 02:29 | | 02:29 | ||
| − | |For example ,''print 1+2''. | + | |For example,'''print 1+2'''. |
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| 02:33 | | 02:33 | ||
| − | |Instead of typing the whole thing,use the up arrow key to go back to the command ''1+2''which we did before | + | |Instead of typing the whole thing, use the '''up-arrow key''' to go back to the command ''1+2'' which we did before. Now use the left-arrow key to navigate to the beginning of the line and type the word "print" and press space. |
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| 02:55 | | 02:55 | ||
| − | | We have changed the line to print 1+2, now press | + | | We have changed the line to print 1+2, now press '''Enter'''. |
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| 03:06 | | 03:06 | ||
| − | | Please note that the indication Out square brackets is not shown here. | + | | Please note that the indication '''Out''' square brackets is not shown here. |
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| 03:11 | | 03:11 | ||
| − | | Now let us do print'' 10 into 2''. | + | | Now, let us do print'' 10 into 2''. |
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| 03:16 | | 03:16 | ||
| − | |We use the up arrow key to navigate to the previous command'' 1+2''. | + | |We use the up-arrow key to navigate to the previous command ''1+2''. |
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|03:22 | |03:22 | ||
| − | | Now change ''1 plus 2 to 10 into 2'' and press | + | | Now, change ''1 plus 2 to 10 into 2'' and press '''Enter'''. |
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| 03:34 | | 03:34 | ||
| − | | Till now, we saw how to invoke the ipython interpreter,quit the ipython and navigate through previous commands in ipython. | + | | Till now, we saw how to invoke the 'ipython interpreter', quit the ipython and navigate through previous commands in ipython. |
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| 03:47 | | 03:47 | ||
| − | | | + | |Let's take an example. Suppose, we want to use the function '''round'''. |
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|03:52 | |03:52 | ||
| − | | For this we just type ''ro'' at the prompt and press the tab key. | + | | For this, we just type '''ro''' at the prompt and press the '''tab''' key. |
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| 04:00 | | 04:00 | ||
| − | | As you can see on the terminal, IPython completes the command ''ro'' into round | + | | As you can see on the terminal, IPython completes the command '''ro''' into '''round'''. This feature of ipython is called the '''tab-completion'''. |
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| 04:08 | | 04:08 | ||
| − | | Let's see some more possibilities of tab completion just type'' r'' and then press the'' tab''. | + | | Let's see some more possibilities of tab completion just type'' r'' and then press the''' tab'''. |
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| 04:19 | | 04:19 | ||
| − | | As you can see that IPython does not complete the command. This is because, there are many possibilities of ''r'' therefore it just lists out all the possible completions of r. | + | | As you can see that IPython does not complete the command. This is because, there are many possibilities of ''r'' therefore it just lists out all the possible completions of 'r'. |
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| 04:31 | | 04:31 | ||
| − | | Now let's try out an exercise. | + | | Now, let's try out an exercise. |
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| 04:33 | | 04:33 | ||
| − | | Pause the video,solve the problem and resume the video. | + | | Pause the video, solve the problem and resume the video. |
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Revision as of 22:40, 22 September 2015
| Time | Narration |
| 00:00 | Hello friends and welcome to the tutorial on Getting started with ipython. |
| 00:07 | At the end of this tutorial, you will be able to:
|
| 00:27 | iPython is an enhanced Python interpreter that provides features like tab-completion, easier access to help and many other functionalities. |
| 00:37 | Let us first see how to start the ipython interpreter. |
| 00:41 | First, open the terminal. Type: "ipython" in the terminal and hit Enter. |
| 00:51 | After getting some information about the version of Python installed and some help commands, we get a prompt with In[1]:. |
| 00:59 | But, if you get an error saying 'ipython is not installed' then refer to the tutorial on how to install the packages. |
| 01:09 | Now, let's see how we can quit the 'ipython interpreter'. Press Ctrl, D. |
| 01:17 | A prompt will appear to confirm whether you really want to exit; type 'y' to say 'yes' and quit 'ipython' and 'n' to say 'no' if you don't want to quit the ipython. |
| 01:28 | Press 'y'. |
| 01:32 | Now, since we have quit the interpreter, let us start it again by typing "ipython". |
| 01:42 | And now let's see, how to use the interpreter. |
| 01:46 | Start with the simplest thing, addition. |
| 01:48 | type: 1+2at the prompt. |
| 01:55 | iPython promptly gives back the output as 3. |
| 01:59 | Notice that the output is displayed with an Out[1] indication. |
| 02:05 | Now, let us try few more operations such as- 5 minus 3, 7 minus 4, 6 into 5. |
| 02:23 | Now, let's see how the ipython remembers the history of commands. |
| 02:29 | For example,print 1+2. |
| 02:33 | Instead of typing the whole thing, use the up-arrow key to go back to the command 1+2 which we did before. Now use the left-arrow key to navigate to the beginning of the line and type the word "print" and press space. |
| 02:55 | We have changed the line to print 1+2, now press Enter. |
| 03:02 | The interpreter prints the result as 3. |
| 03:06 | Please note that the indication Out square brackets is not shown here. |
| 03:11 | Now, let us do print 10 into 2. |
| 03:16 | We use the up-arrow key to navigate to the previous command 1+2. |
| 03:22 | Now, change 1 plus 2 to 10 into 2 and press Enter. |
| 03:34 | Till now, we saw how to invoke the 'ipython interpreter', quit the ipython and navigate through previous commands in ipython. |
| 03:42 | Now, let's see, what is tab-completion?. |
| 03:47 | Let's take an example. Suppose, we want to use the function round. |
| 03:52 | For this, we just type ro at the prompt and press the tab key. |
| 04:00 | As you can see on the terminal, IPython completes the command ro into round. This feature of ipython is called the tab-completion. |
| 04:08 | Let's see some more possibilities of tab completion just type r and then press the tab. |
| 04:19 | As you can see that IPython does not complete the command. This is because, there are many possibilities of r therefore it just lists out all the possible completions of 'r'. |
| 04:31 | Now, let's try out an exercise. |
| 04:33 | Pause the video, solve the problem and resume the video. |
| 04:39 | 1. find out the commands starting with "ab"? |
| 04:44 | 2. list out the commands starting with "a"? |
| 04:54 | ab tab completes toabs and a tab gives us a list of all the commands starting with a. |
| 05:07 | Now, let's see what the functions abs is used for. |
| 05:12 | We will use the help features of ipython to find out this. |
| 05:15 | To see the documentation of a function, type the function name followed by a question mark and hit enter. |
| 05:24 | Ipython interpreter will show the documentation for the function. |
| 05:27 | Let us see the documentation of the function abs, type abs? and press enter |
| 05:38 | As the documentation says, abs accepts a number as an input and returns it's absolute value. |
| 05:46 | lets see few examples, |
| 05:49 | Type abs(-19) and abs(19) on the interpreter. |
| 06:04 | We get 19, as expected, in both the cases. |
| 06:08 | Now lets try it for decimal numbers; lets try abs(-10.5), we got 10.5 as the result. |
| 06:24 | Pause the video here, try out the following exercise and resume the video. |
| 06:31 | Look-up the documentation of round and see how to use it. |
| 06:39 | And you can look up the documentation of the function round by typing round question mark in the ipython interpreter. |
| 06:47 | If you notice, there are extra square brackets around ndigits. |
| 06:53 | This means that ndigits is optional and 0 is the default value. |
| 06:58 | Optional parameters are shown in square brackets in Python documentation. |
| 07:03 | A function round, rounds a number to a given precision. |
| 07:09 | Pause the video here, try out the following exercise and resume the video. |
| 07:16 | let us now try few more examples with the function round. |
| 07:21 | Check the output of round(2.48) round(2.48, 1) round(2.48, 2) round(2.484) round(2.484, 1) round(2.484, 2) |
| 07:43 | Now, we got 2.0, 2.5 and 2.48, which are what we expect. |
| 07:54 | Let's now see how to correct typing errors, which we often make while typing at the terminal. |
| 08:01 | As already shown, if we haven't hit the enter key already, we could navigate using the arrow keys and make deletions using delete or backspace key and correct the errors. |
| 08:12 | let us make a typing error deliberately, type round(2.484 and hit enter, without closing the parenthesis. |
| 08:25 | We get a prompt with dots . |
| 08:28 | This prompt is the continuation prompt of ipython. |
| 08:32 | It appears when, the previous line is incomplete. |
| 08:36 | now complete the command of the same examples with close parenthesis and press enter. |
| 08:49 | We got the expected output that is 2.0 |
| 08:51 | In other instances, if we commit a typing error with a longer and more complex expression and end up with the continuation prompt, we can type Ctrl-C to interrupt the command and get back to the ipython input prompt. |
| 09:15 | Pause the video here, try out the following exercise and resume the video. |
| 09:22 | 1.type round(2.484, and press enter. and then cancel the command using Ctrl-C. |
| 09:45 | 2. type the command, round(2.484, 2) |
| 10:09 | Now, let us revise quickly what we learn't today. In this tutorial,we learn't to, |
| 10:15 | 1. Invoke the ipython interpreter by typing ipython. |
| 10:20 | 2. To quit the ipython interpreter by using ctrl-d. |
| 10:22 | 3. To navigate in the history of ipython by using the arrow keys. |
| 10:28 | 4. What is tab-completion |
| 10:30 | 5. To see the documentation of functions using question mark. |
| 10:34 | 6. To Interrupt using ctrl-c when we make an error. |
| 10:39 | Here are some self assessment questions for you to solve |
| 10:44 | ipython is a programming language similar to Python. |
| 10:50 | ' True or False |
| 10:53 | Second one. Which key combination quits ipython ? Ctrl + C Ctrl + D Alt + C Alt + D |
| 11:03 | And The last one. Which character is used at the end of a command, in Ipython to display the documentation. under score (_) question mark (?) exclamation mark (!) ampersand (&) |
| 11:16 | And the answers are, |
| 11:18 | Ipython is not a programming language, it is just an interpreter. |
| 11:23 | Second one is We use Ctrl D to quit Ipython interpreter. |
| 11:27 | The final one is We use ? at the end of the function name to display its documentation. |
| 11:36 | So we hope you have enjoyed this tutorial and found it useful. |
| 11:39 | Thank you! |
