Difference between revisions of "PERL/C2/Arrays/English-timed"

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|-
 
|-
 
| 00:06
 
| 00:06
−
| In this tutorial, we will learn about  
+
| In this tutorial, we will learn about:
  
 
|-
 
|-
 
|00:09
 
|00:09
−
|'''Index''' of an '''array'''  
+
|* '''Index''' of an '''array'''  
 
   
 
   
 
|-
 
|-
 
|00:11
 
|00:11
−
| Length of an '''array '''
+
|* Length of an '''array '''
 
   
 
   
 
|-
 
|-
 
|00:13
 
|00:13
−
|Accessing '''elements''' of an '''array'''  
+
|* Accessing '''elements''' of an '''array'''  
 
   
 
   
 
|-
 
|-
 
| 00:16
 
| 00:16
−
| Looping over an '''array '''
+
|* Looping over an '''array '''
  
 
|-
 
|-
 
| 00:18
 
| 00:18
−
|'''Sequential Array'''  
+
|* '''Sequential Array''' and
  
 
|-
 
|-
 
| 00:20
 
| 00:20
−
| And '''Array Slicing '''
+
|* '''Array Slicing'''.
  
 
|-
 
|-
 
|00:22
 
|00:22
−
|Here I am using ''' Ubuntu Linux12.04''' operating system and '''Perl 5.14.2'''
+
|Here, I am using ''' Ubuntu Linux 12.04''' operating system and '''Perl 5.14.2'''.
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
|00:37
 
|00:37
−
|You should have basic knowledge of ''' Variables, Comments & Data Structures''' in '''Perl'''
+
|You should have basic knowledge of ''' variables, comments & data Structures''' in '''Perl'''.
  
 
|-
 
|-
 
|00:43
 
|00:43
−
|Knowledge of ''' loops and conditional statements''' will be an added advantage.
+
|Knowledge of '''loops and conditional statements''' will be an added advantage.
 
   
 
   
 
|-
 
|-
 
|00:48
 
|00:48
−
|Please go through the relevant spoken tutorials on the '''spoken tutorial''' website.  
+
|Please go through the relevant spoken tutorials on the '''Spoken Tutorial''' website.  
  
 
|-
 
|-
 
|00:54
 
|00:54
−
|'''Array''' is a simple '''data structure''' which contains '''elements''' of any '''data type'''.   
+
|Array is a simple '''data structure''' which contains '''elements''' of any data type.   
  
 
|-
 
|-
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|-
 
|-
 
| 01:03
 
| 01:03
−
| In '''Perl''', it is not necessary to declare the length of an '''array'''.   
+
| In '''Perl''', it is not necessary to declare the length of an array.   
  
 
|-
 
|-
 
|01:08
 
|01:08
−
|'''Array''' length expands/shrinks as and when elements are added/removed from it.  
+
|Array  length expands/shrinks as and when elements are added/removed from it.  
  
 
|-
 
|-
 
|01:15
 
|01:15
−
| The syntax for declaring an array is -
+
| The syntax for declaring an array is: 
 
   
 
   
 
|-
 
|-
 
|01:18
 
|01:18
−
|'''@myArray equal to open bracket 1 comma  2 comma 3 comma  single quote abc single quote  comma 10.3 close  bracket semicolon'''
+
|'''@myArray equal to open bracket 1 comma  2 comma 3 comma  single quote abc single quote  comma 10.3''' close  bracket semicolon
  
 
|-
 
|-
 
|01:31
 
|01:31
−
|The last index of an array can be found with this command -
+
|The last index of an array can be found with this command: 
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
| 01:42
 
| 01:42
−
|Open the terminal and type  
+
|Open the terminal and type:
  
 
|-
 
|-
Line 113: Line 113:
 
|-
 
|-
 
|01:57
 
|01:57
−
|Type the piece of code that is displayed on screen   
+
|Type the piece of code that is displayed on screen.  
 
    
 
    
 
|-
 
|-
 
|02:02
 
|02:02
−
|Here we have declared & defined an '''array''' which contains 5 elements.  
+
|Here, we have declared & defined an array which contains 5 elements.  
 
   
 
   
 
|-
 
|-
 
|02:07
 
|02:07
−
|As array index starts from zero, the last index value will be 4  
+
|As '''array index''' starts from zero, the last index value will be 4  
 
   
 
   
 
|-
 
|-
 
|02:14
 
|02:14
−
|i.e number of elements, which is 5, minus 1.  
+
|i.e number of elements which is 5, minus 1.  
 
   
 
   
 
|-
 
|-
 
|02:18
 
|02:18
−
|Press Ctrl+S to save the file.  
+
|Press '''Ctrl+S''' to '''save''' the file.  
  
 
|-
 
|-
 
|02:22
 
|02:22
−
|Now switch to  terminal and execute the Perl script
+
|Now, switch to  terminal and execute the Perl script.
  
 
|-
 
|-
 
|02:26
 
|02:26
−
| Type ''' perl arrayIndex dot pl '''
+
| Type: ''' perl arrayIndex dot pl '''
  
 
|-
 
|-
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|-
 
|-
 
|02:32
 
|02:32
−
|The output will be as displayed on the terminal  
+
|The output will be as displayed on the terminal.
 
   
 
   
 
|-
 
|-
 
|02:37
 
|02:37
−
|Now, let us see how to get length of an array in Perl.  
+
|Now, let us see how to get length of an array in '''Perl'''.  
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
|02:53
 
|02:53
−
|Using PERL inbuilt '''scalar function; i.e.  '''scalar''' open bracket '''@array''' close bracket  
+
|Using PERL inbuilt '''scalar function; i.e.  '''scalar''' open bracket '''@array''' close bracket.
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
|  03:14
 
|  03:14
−
| Switch to the terminal and type - 
+
| Switch to the terminal and type: 
  
 
|-
 
|-
Line 185: Line 185:
 
|-
 
|-
 
| 03:27
 
| 03:27
−
|  Type the following piece of code, as shown on the screen-
+
|  Type the following piece of code, as shown on the screen.
 
   
 
   
 
|-
 
|-
 
| 03:32
 
| 03:32
−
|Here we have declared & defined an array which contains 5 elements.  
+
|Here, we have declared & defined an array which contains 5 elements.  
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
|03:41
 
|03:41
−
|Highlighted, are various ways to find the length of an array in Perl.  
+
|Highlighted are various ways to find the length of an array in Perl.  
 
   
 
   
 
|-
 
|-
 
|  03:47
 
|  03:47
−
| Please note We have '''concatenated''' the output in the print statement using comma.  
+
| Please note: We have '''concatenated''' the output in the '''print''' statement using comma.  
 
   
 
   
 
|-
 
|-
 
|03:53
 
|03:53
−
|Press '''Ctrl + S''' to save the file.  
+
|Press '''Ctrl + S''' to '''save''' the file.  
 
    
 
    
 
|-
 
|-
 
|  03:57
 
|  03:57
−
| Now let us execute the script.  
+
| Now, let us execute the script.  
 
   
 
   
 
|-
 
|-
 
|  03:59
 
|  03:59
−
|  Switch to terminal and type-
+
|  Switch to terminal and type:
  
 
|-
 
|-
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|-
 
|-
 
|04:22
 
|04:22
−
|Let us look at an example for accessing elements of an array at -
+
|Let us look at an example for accessing elements of an array at: 
 
   
 
   
 
|-
 
|-
 
|04:27
 
|04:27
−
|First Position  
+
|* First Position  
  
 
|-
 
|-
 
|04:28
 
|04:28
−
|Last Position  
+
|* Last Position  
  
 
|-
 
|-
 
|04:29
 
|04:29
−
|Any position  
+
|* Any position  
 
   
 
   
 
|-
 
|-
 
| 04:32
 
| 04:32
−
| Switch to the terminal and type -
+
| Switch to the terminal and type:
  
 
|-
 
|-
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|-
 
|-
 
|04:49
 
|04:49
−
|Please note-
+
|Please note:
 
   
 
   
 
|-
 
|-
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|-
 
|-
 
|04:54
 
|04:54
−
|But, to access an array element we need to use ''' $ (dollar)''' sign.  
+
|But, to access an array element we need to use '''$'''(dollar) sign.  
  
 
|-
 
|-
 
|04:59
 
|04:59
−
|To access the element at any position, we need to pass '''index''' to an array  
+
|To access the element at any position, we need to pass '''index''' to an array.
  
 
|-
 
|-
 
|05:07
 
|05:07
−
|Here, to access the first element of '''myArray''' ,  
+
|Here, to access the first element of '''myArray''',  
  
 
|-
 
|-
 
|05:11
 
|05:11
−
|zero is passed as '''index. '''
+
|zero is passed as index.
  
 
|-
 
|-
 
|  05:16
 
|  05:16
−
|To access the last element of '''myArray''' , we have passed the last '''index''' of '''myArray.'''
+
|To access the last element of '''myArray''' , we have passed the last index of '''myArray.'''
 
   
 
   
 
|-
 
|-
Line 297: Line 297:
 
|-
 
|-
 
|05:28
 
|05:28
−
| Press Ctrl + S to save the file.  
+
| Press '''Ctrl + S''' to '''save''' the file.  
  
 
|-
 
|-
 
|  05:30
 
|  05:30
−
| Switch to the terminal and execute the  script as -
+
| Switch to the terminal and execute the  script as:
  
 
|-
 
|-
Line 317: Line 317:
 
|-
 
|-
 
|  05:47
 
|  05:47
−
| Now, let us understand, how to '''loop over'''  each element of an array.
+
| Now, let us understand how to '''loop over'''  each element of an array.
  
 
|-
 
|-
 
|05:52
 
|05:52
−
|There are two ways of '''looping over''' an array-
+
|There are two ways of '''looping over''' an array:
 
   
 
   
 
|-
 
|-
 
|  05:56
 
|  05:56
−
| Using '''for loop '''
+
|* Using '''for loop '''
 
    
 
    
 
|-
 
|-
 
|  05:58
 
|  05:58
−
| Using '''foreach loop '''
+
|* Using '''foreach loop '''
  
 
|-
 
|-
Line 337: Line 337:
 
|-
 
|-
 
| 06:07
 
| 06:07
−
|For this, switch to the terminal and type   
+
|For this, switch to the terminal and type:  
  
 
|-
 
|-
Line 345: Line 345:
 
|-
 
|-
 
|06:17
 
|06:17
−
|And Press '''Enter'''
+
|and press '''Enter'''.
 
   
 
   
 
|-
 
|-
 
| 06:20
 
| 06:20
−
| Type the piece of code as shown on the screen  
+
| Type the piece of code as shown on the screen.
  
 
|-
 
|-
Line 357: Line 357:
 
|-
 
|-
 
|  06:31
 
|  06:31
−
| The '''for loop''' will execute till the value of i variable reaches the last '''index''' of an array.  
+
| The '''for''' loop will execute till the value of '''i''' variable reaches the last '''index''' of an array.  
 
   
 
   
 
|-
 
|-
 
|  06:38
 
|  06:38
−
|Here, '''foreach loop''' will be executed for each element of an array.
+
|Here, '''foreach''' loop will be executed for each element of an array.
 
   
 
   
 
|-
 
|-
Line 377: Line 377:
 
|-
 
|-
 
|07:04
 
|07:04
−
| Now, Press Ctrl + S to save the file.  
+
| Now, Press '''Ctrl + S''' to '''save''' the file.  
  
 
|-
 
|-
 
|07:07
 
|07:07
−
|Then switch to the terminal and execute the script as -
+
|Then switch to the terminal and execute the script as:
  
 
|-
 
|-
Line 397: Line 397:
 
|-
 
|-
 
|07:24
 
|07:24
−
| In '''Perl''', we can declare a '''sequential array''' as-
+
| In '''Perl''', we can declare a '''sequential array''' as:
  
 
|-
 
|-
Line 410: Line 410:
 
|07:44
 
|07:44
 
|Similarly, '''@numericArray ''' equal to open bracket 1 dot dot 5 close bracket semicolon  is same as  
 
|Similarly, '''@numericArray ''' equal to open bracket 1 dot dot 5 close bracket semicolon  is same as  
−
'''@numericArray'''  equal to  open bracket 1 comma  2 comma 3 comma  4 comma 5  
+
'''@numericArray'''  equal to  open bracket 1 comma  2 comma 3 comma  4 comma 5.
  
 
|-
 
|-
 
|08:03
 
|08:03
−
|Perl also provides array slicing.  
+
|'''Perl''' also provides '''array slicing'''.  
  
 
|-
 
|-
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|-
 
|-
 
|08:38
 
|08:38
−
|After slicing, the  newArray will look like  
+
|After slicing, the  '''newArray''' will look like  
  
 
|-
 
|-
Line 442: Line 442:
 
|-
 
|-
 
|08:52
 
|08:52
−
|In this tutorial, we have learnt to-
+
|In this tutorial, we have learnt to:
  
 
|-
 
|-
 
|08:55
 
|08:55
−
|Find index of an array  
+
|* Find index of an array  
  
 
|-
 
|-
 
|08:57
 
|08:57
−
|Find length of an array  
+
|* Find length of an array  
  
 
|-
 
|-
 
|08:59
 
|08:59
−
|Access elements of an array  
+
|* Access elements of an array  
  
 
|-
 
|-
 
|09:01
 
|09:01
−
|Loop over an array  
+
|* Loop over an array  
  
 
|-
 
|-
 
|09:03
 
|09:03
−
|Sequenial Array  
+
|* Sequential Array  
  
 
|-
 
|-
 
|09:05
 
|09:05
−
|Array Slicing using sample programs.  
+
|* Array Slicing, using sample programs.  
  
 
|-
 
|-
 
|09:07
 
|09:07
−
|Here is assignment for you -
+
|Here is assignment for you: 
  
 
|-
 
|-
 
|09:10
 
|09:10
−
|Declare an array of rainbow colors  
+
|* Declare an array of rainbow colors  
  
 
|-
 
|-
 
|09:13
 
|09:13
−
|Print 4th element of this array  
+
|* Print 4th element of this array  
  
 
|-
 
|-
 
|09:16
 
|09:16
−
|Print Length and last index of this array  
+
|* Print Length and last index of this array  
  
 
|-
 
|-
 
|09:19
 
|09:19
−
|Loop over each element of an array using for & foreach loops  
+
|* Loop over each element of an array using '''for''' & '''foreach''' loops  
  
 
|-
 
|-
 
|09:25
 
|09:25
−
|Declare array as @myArray = open bracket 1..9 close bracket semicolon and then create an array of odd numbers from above array using array slicing.  
+
|* Declare array as @myArray = open bracket 1..9 close bracket semicolon and then create an array of odd numbers from above array using array slicing.  
  
 
|-
 
|-
 
|09:41
 
|09:41
−
|Watch the video available at the following link
+
|Watch the video available at the following link.
 
   
 
   
 
|-
 
|-
 
|09:44
 
|09:44
−
|It summaries the Spoken Tutorial project
+
|It summaries the Spoken Tutorial project.
 
    
 
    
 
|-
 
|-
 
|09:48
 
|09:48
−
|If you do not have good bandwidth, you can download and watch it
+
|If you do not have good bandwidth, you can download and watch it.
 
   
 
   
 
|-
 
|-
 
| 09:53
 
| 09:53
−
|  The Spoken Tutorial Project Team  Conducts workshops using spoken tutorials
+
|  The Spoken Tutorial project team: Conducts workshops using spoken tutorials.
 
   
 
   
 
|-
 
|-
 
|09:58
 
|09:58
−
|Gives certificates to those who pass an online test
+
|Gives certificates to those who pass an online test.
 
   
 
   
 
|-
 
|-
 
|10:02
 
|10:02
−
|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
 
   
 
   
 
|-
 
|-
 
| 10:09
 
| 10:09
−
|  Spoken Tutorial Project is a part of the Talk to a Teacher project
+
|  "Spoken Tutorial" project is a part of the "Talk to a Teacher" project.
 
    
 
    
 
|-
 
|-
Line 526: Line 526:
 
|-
 
|-
 
|10:20
 
|10:20
−
|More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro
+
|More information on this mission is available at: spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
 
   
 
   
 
|-
 
|-
 
| 10:31
 
| 10:31
−
| Hope you enjoyed this Perl tutorial.  
+
| Hope you enjoyed this Perl tutorial.  
 
   
 
   
 
|-
 
|-
 
|10:35
 
|10:35
−
|This is Amol signing off.
+
|This is Amol, signing off.
 
    
 
    
 
|-
 
|-

Revision as of 12:24, 14 May 2015

Time Narration
00:01 Welcome to the spoken tutorial on Arrays in Perl.
00:06 In this tutorial, we will learn about:
00:09 * Index of an array
00:11 * Length of an array
00:13 * Accessing elements of an array
00:16 * Looping over an array
00:18 * Sequential Array and
00:20 * Array Slicing.
00:22 Here, I am using Ubuntu Linux 12.04 operating system and Perl 5.14.2.
00:30 I will also be using the gedit Text Editor.
00:34 You can use any text editor of your choice.
00:37 You should have basic knowledge of variables, comments & data Structures in Perl.
00:43 Knowledge of loops and conditional statements will be an added advantage.
00:48 Please go through the relevant spoken tutorials on the Spoken Tutorial website.
00:54 Array is a simple data structure which contains elements of any data type.
00:59 Array index starts from zero always.
01:03 In Perl, it is not necessary to declare the length of an array.
01:08 Array length expands/shrinks as and when elements are added/removed from it.
01:15 The syntax for declaring an array is:
01:18 @myArray equal to open bracket 1 comma 2 comma 3 comma single quote abc single quote comma 10.3 close bracket semicolon
01:31 The last index of an array can be found with this command:
01:35 $#myArray
01:38 Let us understand this using sample program.
01:42 Open the terminal and type:
01:44 gedit arrayIndex dot pl space ampersand
01:50 and press Enter.
01:52 This will open arrayIndex dot pl file in geditor
01:57 Type the piece of code that is displayed on screen.
02:02 Here, we have declared & defined an array which contains 5 elements.
02:07 As array index starts from zero, the last index value will be 4
02:14 i.e number of elements which is 5, minus 1.
02:18 Press Ctrl+S to save the file.
02:22 Now, switch to terminal and execute the Perl script.
02:26 Type: perl arrayIndex dot pl
02:30 and press Enter.
02:32 The output will be as displayed on the terminal.
02:37 Now, let us see how to get length of an array in Perl.
02:41 There are many ways by which we can find the length of an array.
02:46 Index of an array + 1 i.e. $#array + 1
02:53 Using PERL inbuilt scalar function; i.e. scalar open bracket @array close bracket.
03:02 Assign array to a scalar variable i.e. $arrayLength = @array
03:09 Let us look at an illustration of array length using a sample program.
03:14 Switch to the terminal and type:
03:18 gedit arrayLength dot pl space ampersand
03:24 Press Enter.
03:27 Type the following piece of code, as shown on the screen.
03:32 Here, we have declared & defined an array which contains 5 elements.
03:38 So, output will display 5.
03:41 Highlighted are various ways to find the length of an array in Perl.
03:47 Please note: We have concatenated the output in the print statement using comma.
03:53 Press Ctrl + S to save the file.
03:57 Now, let us execute the script.
03:59 Switch to terminal and type:
04:02 perl arrayLength dot pl and press Enter.
04:07 The output will be as displayed on the terminal.
04:12 Now, let us understand how to access individual elements in an array.
04:18 Indexing is used to access elements of an array.
04:22 Let us look at an example for accessing elements of an array at:
04:27 * First Position
04:28 * Last Position
04:29 * Any position
04:32 Switch to the terminal and type:
04:35 gedit perlArray dot pl space ampersand
04:42 and press Enter.
04:45 Type the following piece of code as shown.
04:49 Please note:
04:50 myArray is declared with @ (at the rate) sign.
04:54 But, to access an array element we need to use $(dollar) sign.
04:59 To access the element at any position, we need to pass index to an array.
05:07 Here, to access the first element of myArray,
05:11 zero is passed as index.
05:16 To access the last element of myArray , we have passed the last index of myArray.
05:24 Recall, we had learnt about this earlier.
05:28 Press Ctrl + S to save the file.
05:30 Switch to the terminal and execute the script as:
05:36 perl perlArray dot pl
05:41 and press Enter.
05:43 The output will be as shown on the terminal
05:47 Now, let us understand how to loop over each element of an array.
05:52 There are two ways of looping over an array:
05:56 * Using for loop
05:58 * Using foreach loop
06:01 Let's learn how to use these loops to iterate over an array using a sample program.
06:07 For this, switch to the terminal and type:
06:11 gedit loopingOverArray dot pl space ampersand
06:17 and press Enter.
06:20 Type the piece of code as shown on the screen.
06:24 Here, we are printing each element of array by iterating the index.
06:31 The for loop will execute till the value of i variable reaches the last index of an array.
06:38 Here, foreach loop will be executed for each element of an array.
06:46 Once the array reaches its last element, it will exit the foreach loop.
06:53 Please Note: If you are not aware of for and foreach loops,
06:58 please go through the relevant spoken tutorials on spoken tutorial website.
07:04 Now, Press Ctrl + S to save the file.
07:07 Then switch to the terminal and execute the script as:
07:12 perl loopingOverArray dot pl
07:15 and press Enter.
07:19 The output will be as displayed on the terminal.
07:24 In Perl, we can declare a sequential array as:
07:28 @alphaArray = open bracket a dot dot d close bracket semicolon
07:37 i.e alphaArray will contain elements 'a', 'b', 'c' and 'd'
07:44 Similarly, @numericArray equal to open bracket 1 dot dot 5 close bracket semicolon is same as

@numericArray equal to open bracket 1 comma 2 comma 3 comma 4 comma 5.

08:03 Perl also provides array slicing.
08:06 This is nothing but extracting part of an array and dumping it into a new array.
08:13 @array = 19 comma 23 comma 56 comma 45 comma 87 comma 89 close bracket semicolon
08:27 @newArray = @array open square bracket 1 comma 4 close square bracket semicolon
08:38 After slicing, the newArray will look like
08:42 @newArray = open bracket 23 comma 87 close bracket semicolon
08:51 Let us summarize.
08:52 In this tutorial, we have learnt to:
08:55 * Find index of an array
08:57 * Find length of an array
08:59 * Access elements of an array
09:01 * Loop over an array
09:03 * Sequential Array
09:05 * Array Slicing, using sample programs.
09:07 Here is assignment for you:
09:10 * Declare an array of rainbow colors
09:13 * Print 4th element of this array
09:16 * Print Length and last index of this array
09:19 * Loop over each element of an array using for & foreach loops
09:25 * Declare array as @myArray = open bracket 1..9 close bracket semicolon and then create an array of odd numbers from above array using array slicing.
09:41 Watch the video available at the following link.
09:44 It summaries the Spoken Tutorial project.
09:48 If you do not have good bandwidth, you can download and watch it.
09:53 The Spoken Tutorial project team: Conducts workshops using spoken tutorials.
09:58 Gives certificates to those who pass an online test.
10:02 For more details, please write to contact at: spoken hyphen tutorial dot org
10:09 "Spoken Tutorial" project is a part of the "Talk to a Teacher" project.
10:13 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
10:20 More information on this mission is available at: spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
10:31 Hope you enjoyed this Perl tutorial.
10:35 This is Amol, signing off.
10:37 Thanks for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Sandhya.np14

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