Pratik kamble: Created page with "{|Border=1 |'''Time''' |'''Narration''' |- |00:01 |Welcome to the spoken tutorial on '''Getting started with''' '''functions'''. |- |00:06 |In this tutorial, we will learn..."

2019-06-10T08:50:26Z

Created page with "{|Border=1 |'''Time''' |'''Narration''' |- |00:01 |Welcome to the spoken tutorial on '''Getting started with''' '''functions'''. |- |00:06 |In this tutorial, we will learn..."

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{|Border=1
|'''Time'''
|'''Narration'''

|-
|00:01
|Welcome to the spoken tutorial on '''Getting started with''' '''functions'''.

|-
|00:06
|In this tutorial, we will learn to,

Define a '''function'''

Define '''functions''' with '''arguments''' and

use '''docstrings'''.

|-
| 00:17
|To record this tutorial, I am using

'''Ubuntu Linux 16.04''' operating system

'''Python 3.4.3 '''and

'''IPython 5.1.0'''

|-
| 00:32
| To practise this tutorial, you should know how to use '''tuples.'''

If not, see the relevant '''Python''' tutorials on this website.

|-
|00:44
| First we will learn about functions.

|-
|00:48
|A '''function''' is a portion of '''code''' within a larger '''program''' that performs a specific task.

|-
|00:55
|'''Functions '''are useful in reusing the '''code''' and eliminate code redundancy.

|-
|01:01
|'''Functions''' are also used to organise our code into manageable blocks.

|-
| 01:07
| Here is the syntax for defining the '''functions'''.

|-
| 01:11
|'''def''' is the '''keyword '''which defines the '''function''' name.

|-
| 01:15
|colon is used to mark the end of the '''function''' name.

|-
| 01:19
|'''docstring''' is the documentation string to describe what the '''function''' does.

It is an optional, but recommended.

|-
| 01:29
|'''Statement''' makes the function body and it must have 4 indentation level.

|-
| 01:36
|'''return''' statement is to return a value from the function and it is also indented by 4 spaces.

|-
| 01:44
| Now we will understand the '''functions''' with an example.

|-
| 01:49
|Consider a mathematical '''function''' '''f''' ''of''''' x''''' is equal to'' '''x''' ''squared''.

|-
| 01:55
|Here '''x''' is a '''variable'''. '''f '''''of '''''x''' changes when '''x''' changes.

|-
| 02:02
|Let us define our '''function f '''''of '''''x.'''

|-
| 02:06
|The first line '''def f '''''of''''' x '''is used to define the '''function''' '''name''' and its '''parameters.'''

|-
| 02:13
|The second line uses the '''function parameters''' to return the required value.

|-
| 02:19
| Let us start '''ipython.'''

Open the '''terminal'''.

|-
| 02:24
| Type '''ipython3 '''and press '''Enter'''.

|-
| 02:29
|From here onwards, remember to press the '''Enter''' key after typing every command on the '''terminal'''.

|-
| 02:36
| Type,

'''def f '''''inside brackets '''''x '''''colon'' '''return x '''asterisk '''x'''

and press the '''Enter''' key two times.

|-
| 02:47
| Let us call the '''f '''''of''' ''x '''with different '''arguments.'''

|-
| 02:51
|Type,

'''f '''''inside brackets '''''2'''

'''f '''''inside brackets '''''2.5'''

It returned 4 and 6.25 respectively.

|-
| 03:05
| Now let us see how to write '''functions''' without '''arguments'''.

|-
| 03:10
|Type the code as shown.

It defines a new '''function''' named '''greet''' which will print '''"No function arguments"'''

|-
| 03:21
| Now we will call the '''function''' as,'''greet '''''open and close parentheses''

|-
| 03:28
| Note that it is not mandatory for a '''function''' to '''return''' '''values'''.

|-
| 03:33
|The '''function greet''' neither takes any '''arguments''' nor '''returns''' any '''value'''.

|-
|03:40
| Next we will learn how to '''comment''' in a '''code'''.

|-
|03:44
|'''Documenting/commenting code''' is a good practice.

|-
|03:48
|'''Docstrings''' are triple quoted '''comments''' entered just after the '''function''' '''definition'''.

It implies what the '''function''' does.

|-
| 03:57
| Let us write a '''function '''which '''returns average '''of two numbers.

|-
| 04:02
|Type the code as shown. and press the '''Enter''' key two times.

'''Comments''' within triple quotes give a clear explanation about the '''code'''.

|-
| 04:14
| Type, '''avg '''''question mark''

Here we can see the '''docstring '''of the '''function avg.'''

|-
| 04:23
| Now let us pass 3 and 5 as values to the '''arguments a''' and '''b''' to the '''function avg.'''

|-
|04:31
|Type, '''avg '''''inside brackets''''' 3 '''''comma''''' 5''' We get 4.0 as output.

|-
|04:41
|Pause the video.Try this exercise and then resume the video.

|-
| 04:47
| Write a '''function circle '''which returns the '''area''' and '''perimeter''' of a '''circle''' with given radius '''r'''.

|-
| 04:54
| Switch back to the '''terminal''' for the solution.

|-
|04:58
|Type the '''code''' as shown. Press the '''Enter''' key two times.

|-
| 05:05
|The '''circle function''' requires us to '''return''' two values.

|-
|05:10
|A '''python function''' can return any number of values in the form of a '''tuple'''.

|-
|05:16
|Let us call the '''function circle''' as, '''a '''''comma''''' p '''''is equal to''''' circle '''''inside brackets '''''6'''

|-
| 05:25
|Now Type, '''print '''''inside brackets '''''a '''''comma''''' p'''

|-
| 05:31
|We can see the output as area and perimeter of a circle of radius 6.

|-
| 05:38
|This brings us to the end of this tutorial. Let us summarize.

|-
| 05:44
|In this tutorial, we have learnt to,

Define '''functions''' in '''Python'''

Call a '''function''' by specifying the '''function''' name

|-
| 05:54
|Write '''docstrings''' to a '''function''' by putting it as a triple quoted '''string'''

Pass '''parameters''' to a '''function'''

Return '''values''' from a '''function'''.

|-
| 06:06
| Here are some self assessment questions for you to solve

1. How many '''arguments''' can be passed to a '''Python function'''?

|-
|06:15
|2.Write a '''function''' to find the area of a rectangle.

|-
| 06:20
| And the answers,

1. Any number of '''arguments''' can be passed to a '''Python function'''.

|-
|06:28
|2. We can write a '''function''' to find the area of a rectangle as:'''def rectangle''''' underscore '''''area '''''inside brackets '''''l '''''comma''''' b '''''colon''
'''return l '''''asterisk''''' b '''

|-
|06:42
| Please post your timed queries in this forum.

|-
|06:46
| Please post your general queries on Python in this forum.

|-
| 06:51
| FOSSEE team coordinates the TBC project.

|-
| 06:55
|Spoken Tutorial Project is funded by NMEICT, MHRD, Govt. of India. For more details, visit this website.

|-
|07:04
|This is Priya from IIT Bombay signing off. Thanks for watching.

|}

Python-3.4.3/C4/Getting-Started-with-Functions/English-timed - Revision history

Pratik kamble: Created page with "{|Border=1 |'''Time''' |'''Narration''' |- |00:01 |Welcome to the spoken tutorial on '''Getting started with''' '''functions'''. |- |00:06 |In this tutorial, we will learn..."