Difference between revisions of "PERL/C2/Functions-in-Perl/English-timed"

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|-
 
|-
 
|00:10
 
|00:10
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|* PERL '''functions'''  
+
| PERL '''functions''', '''functions''' with '''arguments'''
−
+
−
|-
+
−
|00:11
+
−
|* '''functions''' with '''arguments'''
+
 
   
 
   
 
|-
 
|-
 
|00:13
 
|00:13
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|* ''' function''' with '''return values'''.  
+
|'''functions''' with '''return values'''.  
  
 
|-
 
|-
 
|00:16
 
|00:16
−
|For this tutorial, I am using  
+
|For this tutorial, I am using:
 
   
 
   
 
|-
 
|-
 
| 00:18
 
| 00:18
−
|* '''Ubuntu Linux 12.04''' operating system  
+
|'''Ubuntu Linux 12.04''' operating system  
  
 
|-
 
|-
 
| 00:22
 
| 00:22
−
|* ''' Perl 5.14.2''' and  
+
|''' Perl 5.14.2''' and  
  
 
|-
 
|-
 
| 00:24
 
| 00:24
−
|* ''' gedit''' Text Editor.  
+
|''' gedit''' Text Editor.  
  
 
|-
 
|-
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|-
 
|-
 
| 00:41
 
| 00:41
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| Please go through the relevant spoken tutorials on the '''spoken tutorial''' website.   
+
| Please go through the relevant spoken tutorials on the '''Spoken Tutorial''' website.   
 
   
 
   
 
|-
 
|-
 
|00:47
 
|00:47
−
|We will first see some simple '''PERL functions.'''
+
|We will first see some simple PERL''' functions.'''
  
 
|-
 
|-
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|-
 
|-
 
|01:07
 
|01:07
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| And, it does not '''return''' anything.  
+
| And, it does not return anything.  
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
|01:24
 
|01:24
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|To include the '''module''' file in the script, one has to use the following syntax-
+
|To include the '''module''' file in the script, one has to use the following syntax:
  
 
|-
 
|-
 
|01:31
 
|01:31
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| ''' use ModuleFileName semicolon '''
+
| ''' use ModuleFileName''' semicolon
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
|01:39
 
|01:39
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|Open a file in your text editor and name it as '''simpleFunction dot pl'''
+
|Open a file in your text editor and name it as '''simpleFunction dot pl'''.
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
|02:06
 
|02:06
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|This is the declaration & definition of the '''function.'''
+
|This is the declaration & definition of the function.  
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
|02:17
 
|02:17
−
|Then switch to the terminal and execute the PERL '''script''' by typing  
+
|Then switch to the terminal and execute the PERL '''script''' by typing:
  
 
|-
 
|-
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|-
 
|-
 
|02:38
 
|02:38
−
|Now, let us see a function with arguments.
+
|Now, let us see a '''function''' with '''arguments'''.
 
   
 
   
 
|-
 
|-
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|-
 
|-
−
| 02:48
+
|02:48
 
| Open a file in your text editor and name it as '''functionWithArgs dot pl'''.
 
| Open a file in your text editor and name it as '''functionWithArgs dot pl'''.
 
   
 
   
 
|-
 
|-
−
|   02:57
+
|02:57
 
|Here is my '''functionWithArgs''' script in '''gedit. '''
 
|Here is my '''functionWithArgs''' script in '''gedit. '''
  
 
|-
 
|-
−
| 03:02
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|03:02
 
| Type the following piece of code as shown on the screen.  
 
| Type the following piece of code as shown on the screen.  
 
   
 
   
 
|-
 
|-
 
|03:07
 
|03:07
−
|Here, we are calling a function with  arguments, 10 and 20.  
+
|Here, we are calling the '''function''' with  arguments 10 and 20.  
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
| 03:20
 
| 03:20
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|'''@_''' is a special PERL variable. We will cover its details in future tutorials.  
+
|'''@_''' is a special '''Perl''' variable. We will cover its details in future tutorials.  
  
 
|-
 
|-
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|-
 
|-
−
| 03:42
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|03:42
−
| '''@_'''is a special PERL array.  
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| '''@_'''is a special '''Perl''' array.  
 
   
 
   
 
|-
 
|-
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|-
 
|-
−
| 03:51
+
|03:51
 
| Similarly, we can catch the passed  arguments in  variables as:  
 
| Similarly, we can catch the passed  arguments in  variables as:  
  
 
|-
 
|-
−
|   03:56
+
|03:56
−
| '''$var1 space = space  shift @_''' semicolon
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|'''$var1 space = space  shift @_''' semicolon
 
   
 
   
 
|-
 
|-
−
| 04:04
+
|04:04
 
|'''$var2 space  = space  shift @_'''  semicolon
 
|'''$var2 space  = space  shift @_'''  semicolon
  
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|-
 
|-
 
|04:24
 
|04:24
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|Another way is: '''$var1 space  =  space dollar underscore open square bracket zero close square bracket''' semicolon  
+
|Another way is: '''$var1 space  =  space dollar underscore open square bracket zero close square bracket''' semicolon.
  
 
|-
 
|-
 
|04:38
 
|04:38
−
| ''' $var2 space  =  space dollar underscore open square bracket 1 close square bracket''' semicolon
+
| '''$var2 space  =  space dollar underscore open square bracket 1 close square bracket''' semicolon.
 
   
 
   
 
|-
 
|-
 
|04:49
 
|04:49
−
|The above mentioned way is similar to fetching '''elements''' of '''@_ array''' using '''index.'''
+
|The above mentioned way is similar to the fetching '''elements''' of '''@_ array''' using '''index.'''
  
 
|-
 
|-
 
|04:59
 
|04:59
−
|Now, switch to terminal and execute the script by typing:  
+
|Now, switch to '''terminal''' and execute the '''script''' by typing:  
  
 
|-
 
|-
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|-
 
|-
 
| 05:23
 
| 05:23
−
| Now, let us look at a functions which returns a single value.  
+
| Now, let us look at a function which returns a single value.  
  
 
|-
 
|-
 
|05:32
 
|05:32
−
|Let us understand the same using a sample program.  
+
|Let us understand the same, using a sample program.  
  
 
|-
 
|-
 
|05:35
 
|05:35
−
|Let me switch to ''' funcWithSingleRtrnVal dot pl ''' script in '''gedit.'''
+
|Let me switch to '''funcWithSingleRtrnVal dot pl''' script in '''gedit.'''
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
|05:52
 
|05:52
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|Here, we are calling ''' addVariables function''' with '''parameters''' 10 and 20.  
+
|Here, we are calling ''' addVariables''' function with '''parameters''' 10 and 20.  
 
   
 
   
 
|-
 
|-
 
|06:01
 
|06:01
−
|The return value of the  function is caught in ''' $addition''' variable.
+
|The return value of the  function is caught in '$addition' variable.
  
 
|-
 
|-
 
|06:09
 
|06:09
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|This function does the addition of the passed parameters and returns the answer.  
+
|This function does the addition of the passed '''parameters''' and returns the answer.  
  
 
|-
 
|-
 
|06:15
 
|06:15
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|Save the file.  
+
|'''Save''' the file.  
 
   
 
   
 
|-
 
|-
 
|06:17
 
|06:17
−
|Now let us execute the script.  
+
|Now, let us '''execute''' the '''script'''.  
  
 
|-
 
|-
−
| 06:20
+
|06:20
−
|So, switch to terminal and type:  
+
|So, switch to '''terminal''' and type:  
  
 
|-
 
|-
−
| 06:24
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|06:24
 
|''' perl funcWithSingleRtrnVal dot pl'''  and press '''Enter.'''  
 
|''' perl funcWithSingleRtrnVal dot pl'''  and press '''Enter.'''  
  
 
|-
 
|-
 
|06:35
 
|06:35
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| The output is as displayed on the terminal.  
+
| The '''output''' is as displayed on the terminal.  
 
   
 
   
 
|-
 
|-
−
| 06:43
+
|06:43
 
| Now, let us see a function which returns multiple values.  
 
| Now, let us see a function which returns multiple values.  
 
   
 
   
 
|-
 
|-
−
| 06:48
+
|06:48
 
| Let us understand the same, using a sample program.  
 
| Let us understand the same, using a sample program.  
  
 
|-
 
|-
−
| 06:53
+
|06:53
−
| In gedit, I have opened a file and named it as ''' funcWithMultipleRtrnVals dot pl'''.  
+
| In '''gedit''', I have opened a file and named it as ''' funcWithMultipleRtrnVals dot pl'''.  
  
 
|-
 
|-
−
| 07:04
+
|07:04
−
|Please do like wise in your text editor.
+
|Please do like-wise in your '''text editor'''.
  
 
|-
 
|-
−
| 07:08
+
|07:08
 
| Now, type the following piece of code as shown.  
 
| Now, type the following piece of code as shown.  
  
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|-
 
|-
−
| 07:21
+
|07:21
 
| The return values of the function are caught in variables ''' $var1, $var2 and  $addition'''.  
 
| The return values of the function are caught in variables ''' $var1, $var2 and  $addition'''.  
 
   
 
   
 
|-
 
|-
−
| 07:31
+
|07:31
 
| This function does the addition and returns the passed parameters and the resultant answer.  
 
| This function does the addition and returns the passed parameters and the resultant answer.  
  
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|-
 
|-
 
| 07:53
 
| 07:53
−
|Similarly, this demonstrates how ''' hash''' can be returned from a function.  
+
|Similarly, this demonstrates how '''hash''' can be returned from a function.  
  
 
|-
 
|-
 
|08:00
 
|08:00
−
| Save your file.  
+
| '''Save''' your file.  
  
 
|-
 
|-
 
|08:03
 
|08:03
−
| Now let us execute the PERL script on the terminal by typing:  
+
| Now let us execute the '''Perl''' script on the terminal by typing:  
 
   
 
   
 
|-
 
|-
−
| 08:10
+
|08:10
 
| '''perl funcWithMultipleRtrnVals dot pl '''
 
| '''perl funcWithMultipleRtrnVals dot pl '''
  
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|-
 
|-
−
| 08:20
+
|08:20
 
| The output is as displayed on the terminal.
 
| The output is as displayed on the terminal.
  
 
|-
 
|-
−
| 08:32
+
|08:32
−
|PERL provides several inbuilt functions.
+
|'''Perl''' provides several inbuilt functions.
  
 
|-
 
|-
 
|08:36
 
|08:36
−
| We learnt some of them in earlier tutorials. For eg- ''' Arrays, Hash, sort, scalar, each, keys''' etc.  
+
| We learnt some of them in earlier tutorials. For e.g- ''' arrays, Hash, sort, scalar, each, keys''' etc.  
 
   
 
   
 
|-
 
|-
 
|08:49
 
|08:49
−
|Calling inbuilt functions, similar to calling any other function which we define  
+
|Calling inbuilt functions is similar to calling any other function which we define.
  
 
|-
 
|-
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|-
 
|-
 
|09:17
 
|09:17
−
|* '''functions''' in PERL
+
|'''functions''' in '''Perl'''
  
 
|-
 
|-
 
|09:19
 
|09:19
−
|* '''functions''' with '''arguments''' and   
+
|'''functions''' with '''arguments''' and   
  
 
|-
 
|-
 
|09:22
 
|09:22
−
|* '''functions''' which '''return''' values using sample programs.  
+
| '''functions''' which return values using sample programs.  
  
 
|-
 
|-
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|-
 
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|09:29
 
|09:29
−
|Write a '''function''' which takes 3 '''arguments. '''
+
|Write a '''function''' which takes 3 '''arguments.'''
  
 
|-
 
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|-
 
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|09:37
 
|09:37
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|Return the result of the action performed on the '''arguments''' and print the same.  
+
|'''Return''' the result of the action performed on the '''arguments''' and print the same.  
  
 
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|-
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|09:47
 
|09:47
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|It summaries the Spoken Tutorial project.
+
|It summarizes the Spoken Tutorial project.
 
   
 
   
 
|-
 
|-
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|-
 
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| 09:56
 
| 09:56
−
|  The Spoken Tutorial project team: Conducts workshops using spoken tutorials.
+
|  The Spoken Tutorial project team: * Conducts workshops using spoken tutorials.
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
|10:07
 
|10:07
−
|For more details, please write to contact at: spoken hyphen tutorial dot org.
+
|For more details, please write to: contact at spoken hyphen tutorial dot org.
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
| 10:40
 
| 10:40
−
| Hope you enjoyed this PERL tutorial.  
+
| Hope you enjoyed this '''Perl''' tutorial.  
 
   
 
   
 
|-
 
|-

Latest revision as of 15:52, 10 March 2017

Time Narration
00:01 Welcome to the spoken tutorial on Functions in PERL.
00:06 In this tutorial, we will learn about:
00:10 PERL functions, functions with arguments
00:13 functions with return values.
00:16 For this tutorial, I am using:
00:18 Ubuntu Linux 12.04 operating system
00:22 Perl 5.14.2 and
00:24 gedit Text Editor.
00:27 You can use any text editor of your choice.
00:31 You should have basic knowledge of variables, comments, loops, conditional statements and data Structures in PERL.
00:41 Please go through the relevant spoken tutorials on the Spoken Tutorial website.
00:47 We will first see some simple PERL functions.
00:51 In PERL, functions, also called as subroutines, are declared with sub keyword.
00:57 The definition of a declared function is written between curly braces.
01:03 This function does not take any arguments.
01:07 And, it does not return anything.
01:10 Note: function definition can be written anywhere in the script or in another module.
01:17 This module must then be included in the script, to use this function.
01:24 To include the module file in the script, one has to use the following syntax:
01:31 use ModuleFileName semicolon
01:35 Let us understand this using a sample program.
01:39 Open a file in your text editor and name it as simpleFunction dot pl.
01:46 Here is my simpleFunction dot pl file in gedit.
01:51 Type the code as displayed on the screen.
01:55 Here, we are just calling a function which we have defined.
02:00 Then the execution control is passed to that function.
02:06 This is the declaration & definition of the function.
02:10 This function will print out the given text.
02:14 Save your file.
02:17 Then switch to the terminal and execute the PERL script by typing:
02:24 perl simpleFunction dot pl
02:28 and press Enter.
02:30 The output will be as shown on the terminal.
02:38 Now, let us see a function with arguments.
02:44 Let us understand this function using a sample program.
02:48 Open a file in your text editor and name it as functionWithArgs dot pl.
02:57 Here is my functionWithArgs script in gedit.
03:02 Type the following piece of code as shown on the screen.
03:07 Here, we are calling the function with arguments 10 and 20.
03:13 The passed arguments are caught in '$var1' & '$var2'.
03:20 @_ is a special Perl variable. We will cover its details in future tutorials.
03:29 This function performs the addition of 2 variables and prints the answer.
03:37 Save your file.
03:42 @_is a special Perl array.
03:46 This array is used to store the passed arguments.
03:51 Similarly, we can catch the passed arguments in variables as:
03:56 $var1 space = space shift @_ semicolon
04:04 $var2 space = space shift @_ semicolon
04:12 shift @_ removes the element at first position from @_ array
04:21 and assigns it to a variable.
04:24 Another way is: $var1 space = space dollar underscore open square bracket zero close square bracket semicolon.
04:38 $var2 space = space dollar underscore open square bracket 1 close square bracket semicolon.
04:49 The above mentioned way is similar to the fetching elements of @_ array using index.
04:59 Now, switch to terminal and execute the script by typing:
05:06 perl functionWithArgs dot pl and press Enter .
05:14 The output is as displayed on the screen.
05:23 Now, let us look at a function which returns a single value.
05:32 Let us understand the same, using a sample program.
05:35 Let me switch to funcWithSingleRtrnVal dot pl script in gedit.
05:46 Open a file in your text editor and type the following piece of code as shown.
05:52 Here, we are calling addVariables function with parameters 10 and 20.
06:01 The return value of the function is caught in '$addition' variable.
06:09 This function does the addition of the passed parameters and returns the answer.
06:15 Save the file.
06:17 Now, let us execute the script.
06:20 So, switch to terminal and type:
06:24 perl funcWithSingleRtrnVal dot pl and press Enter.
06:35 The output is as displayed on the terminal.
06:43 Now, let us see a function which returns multiple values.
06:48 Let us understand the same, using a sample program.
06:53 In gedit, I have opened a file and named it as funcWithMultipleRtrnVals dot pl.
07:04 Please do like-wise in your text editor.
07:08 Now, type the following piece of code as shown.
07:13 Here, we are calling addVariables function with parameters 10 and 20.
07:21 The return values of the function are caught in variables $var1, $var2 and $addition.
07:31 This function does the addition and returns the passed parameters and the resultant answer.
07:42 This illustration demonstrates how we can return an array from a function.
07:53 Similarly, this demonstrates how hash can be returned from a function.
08:00 Save your file.
08:03 Now let us execute the Perl script on the terminal by typing:
08:10 perl funcWithMultipleRtrnVals dot pl
08:18 and press Enter.
08:20 The output is as displayed on the terminal.
08:32 Perl provides several inbuilt functions.
08:36 We learnt some of them in earlier tutorials. For e.g- arrays, Hash, sort, scalar, each, keys etc.
08:49 Calling inbuilt functions is similar to calling any other function which we define.
08:57 e.g sort open bracket @arrayName close bracket semicolon.
09:04 Try incorporating some inbuilt functions in the sample programs we used.
09:10 And observe their outputs.
09:13 Let us summarize.
09:15 In this tutorial, we have learnt:
09:17 functions in Perl
09:19 functions with arguments and
09:22 functions which return values using sample programs.
09:27 Here is an assignment for you:
09:29 Write a function which takes 3 arguments.
09:33 Perform some action on these arguments.
09:37 Return the result of the action performed on the arguments and print the same.
09:43 Watch the video available at the following link.
09:47 It summarizes the Spoken Tutorial project.
09:51 If you do not have good bandwidth, you can download and watch it.
09:56 The Spoken Tutorial project team: * Conducts workshops using spoken tutorials.
10:02 Gives certificates to those who pass an online test.
10:07 For more details, please write to: contact at spoken hyphen tutorial dot org.
10:14 "Spoken Tutorial" project is a part of the "Talk to a Teacher" project.
10:19 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
10:28 More information on this mission is available at: spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
10:40 Hope you enjoyed this Perl tutorial.
10:43 This is Amol, signing off.
10:46 Thanks for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Sandhya.np14

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