Difference between revisions of "PERL/C2/Array-functions/English-timed"

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| In this tutorial, we will learn about '''Array functions''' in '''PERL''' like:  
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| In this tutorial, we will learn about '''array functions''' in '''PERL''' like:  
  
 
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|* '''push '''
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|'''push ''', '''pop''' , '''shift'''
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|* '''pop'''  
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|* '''shift'''
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|* '''unshift '''
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|'''unshift ''',  '''split'''
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|* '''split'''
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|* '''splice '''and
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| '''splice '''and '''join'''
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|* '''join'''
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|* '''sort'''
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|'''sort''', '''qw'''.
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|* '''qw'''.
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|This can be done by using:
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|This can be done by using  
  
 
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|'''unshift''' function which adds an '''element''' to an '''array''' at the 1st position.  
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| '''unshift''' function which adds an '''element''' to an '''array''' at the 1st position.  
 
   
 
   
 
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|'''shift''' function which removes the first '''element''' from an '''array'''.  
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| '''shift''' function which removes the first '''element''' from an '''array'''.  
 
   
 
   
 
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|'''2nd''' is the '''string''' which needs to be split.  
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|2nd is the '''string''' which needs to be split.  
  
 
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|Let us summarize.  
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|Let us summarize. In this tutorial, we have learnt to:   
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|In this tutorial, we have learnt to:   
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|* add/remove '''elements'''  from an '''array '''
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|add/remove '''elements'''  from an '''array '''
  
 
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|* basic functions which can be performed on '''array''' using sample program.  
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| basic functions which can be performed on '''array''' using sample program.  
  
 
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|Here is assignment for you -   
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|Here is an assignment for you -   
  
 
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|* split the above '''string''' at '/ '  (forward slash) '''delimiter'''
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| Split the above '''string''' at '/ '  (forward slash) '''delimiter'''.
  
 
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|* Add ''' https:// ''' at the start of a newly created '''array'''   
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| Add '''https://''' at the start of a newly created '''array'''.  
  
 
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|* Remove '''element “Perl”''' from the '''array'''
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|Remove '''element “Perl”''' from the '''array'''.
  
 
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|* Declare a number array  and sort it.  
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|Declare a number array  and sort it.  
  
 
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| Hope you enjoyed this '''PERL''' tutorial.  
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| Hope you enjoyed this '''Perl''' tutorial.  
 
   
 
   
 
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Latest revision as of 15:47, 10 March 2017

Time Narration
00:01 Welcome to the spoken tutorial on Array Functions in PERL.
00:06 In this tutorial, we will learn about array functions in PERL like:
00:11 push , pop , shift
00:14 unshift , split
00:16 splice and join
00:18 sort, qw.
00:20 I am using Ubuntu Linux 12.04 operating system and Perl 5.14.2.
00:28 I will also be using the gedit Text Editor.
00:32 You can use any text editor of your choice.
00:36 You should have basic knowledge of variables, data Structures and arrays in PERL.
00:43 Knowledge of comments, 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 Perl provides certain inbuilt functions.
00:57 These functions can perform various operations on an array.
01:02 Let us first learn how to add and remove elements from the last position of an array.
01:08 This can be done by using
01:10 push function which adds an element at the last position of an array
01:15 and pop function which removes an element from the last position of an array.
01:21 Let us understand push and pop functions by using a sample program.
01:26 Open the terminal and type: gedit perlArray dot pl space ampersand
01:33 and press Enter.
01:36 This will open 'perlArray dot pl' file in gedit.
01:41 Type the code as shown on the screen.
01:45 Here, we have declared an array of length 3.
01:50 push function will insert an element at the last position of this array i.e after 3
01:57 whereas pop function will remove an element from the last position of the array.
02:04 In our case, 4 will be removed from the array.
02:08 Press Ctrl + S to save the file.
02:11 push function takes 2 arguments-
02:14 1st argument to the push function is the array in which to add an element.
02:20 2nd argument is the element which is to be pushed into the array.
02:25 The syntax of pop function is as follows:
02:29 pop function takes only one argument.
02:32 It is the array from which an element needs to be removed.
02:36 Note: Both these functions work at the last position of an array.
02:41 The element removed by pop function can be collected into another variable.
02:46 The syntax for this is $variable space = space pop open bracket @myArray close bracket .
02:57 Now switch to the terminal and execute the Perl script.
03:01 Type: perl perlArray dot pl and press Enter.
03:07 The output is as shown on the terminal.
03:11 Now, let us see how to add/remove an element from the 1st position of an array.
03:18 This can be achieved using-
03:20 unshift function which adds an element to an array at the 1st position.
03:25 shift function which removes the first element from an array.
03:31 Let us understand this using a sample program.
03:35 I will open perlArray dot pl file which I have already created.
03:39 Type the following piece of code as shown on the screen.
03:43 unshift function will insert an element at the first position i.e before 1.
03:52 shift function will remove an element from the first position.
03:57 In our case, zero will be removed.
04:00 Press Ctrl + S to save the file.
04:03 The unshift function takes 2 arguments-
04:06 1st argument is the array in which to add an element,
04:10 2nd argument is the element to be added into the array .
04:15 shift function takes only one argument -
04:18 This is the array from which the element needs to be removed.
04:22 Note: Both these functions work at first position of an array.
04:27 We can collect the element removed by shift function into some variable.
04:33 The syntax for this is: $variable space = space shift open bracket @myArray close bracket.
04:44 Then switch to the terminal and execute the Perl script.
04:48 Type: perl perlArray dot pl and press Enter.
04:54 The output displayed on the terminal is as highlighted.
04:59 Now, let us see how to remove an element from a specified position of an array.
05:05 splice function removes an element from a specified position of an array.
05:11 The return value of this function is an array of removed elements.
05:17 Let us understand this using a sample program.
05:21 Go to the perlArray dot pl file which we created earlier.
05:26 Type the piece of code as shown on the screen.
05:30 We need to provide index from where we want to remove the elements and
05:35 the offset up to which we want to remove the elements.
05:39 In our case, the elements 5 and 6 will be removed.
05:44 Then switch to the terminal and execute the Perl script by typing:
05:49 perl perlArray dot pl and press Enter.
05:55 The output is as shown on the terminal.
05:59 Now, let us look at few other inbuilt functions of arrays.
06:04 split function is used to divide a string at a specified delimiter.
06:10 The return value of this function is an array.
06:14 The elements of this array are the divided portions of the string.
06:19 join function joins the elements of an array using the specified delimiter.
06:25 It returns a string of joined elements.
06:28 sort function sorts an array in alphabetical/numerical order.
06:34 qw function returns an array of words, separated by a white space.
06:40 Now, let us understand all these functions using a sample program.
06:45 Switch to terminal and type:
06:48 gedit arrayFunctions dot pl space ampersand and press Enter.
06:55 Type the following piece of code as shown on screen.
07:00 In this case, each word of the variable string will become an element of an array.
07:07 Here, each element of newArray will be joined by comma.
07:12 sort function will sort the elements of an array in alphabetical order.
07:19 qw function creates an array of words separated by space.
07:25 Let us understand each function.
07:28 split function takes two arguments.
07:31 1st argument is the delimiter by which the string needs to be split,
07:36 2nd is the string which needs to be split.
07:39 Delimiters can be specified in forward slash, single or double quotes.
07:45 join function takes 2 arguments.
07:48 1st is the delimiter by which the array elements need to be joined.
07:53 2nd is the array.
07:55 Delimiters can be specified in single or double quotes.
07:58 sort function takes a single argument which is the array that needs to be sorted.
08:05 qw function returns an array of words, separated by space.
08:11 It is not necessary to specify the word in quotes if written using qw.
08:17 Then switch to the terminal and execute the Perl script by typing:
08:23 perl arrayFunctions dot pl
08:26 and press Enter.
08:29 The following output is displayed on the screen.
08:33 Let us summarize. In this tutorial, we have learnt to:
08:36 add/remove elements from an array
08:40 basic functions which can be performed on array using sample program.
08:46 Here is an assignment for you -
08:48 'script.spoken-tutorial.org/index.php/Perl'
08:54 Split the above string at '/ ' (forward slash) delimiter.
08:59 Add https:// at the start of a newly created array.
09:06 Remove element “Perl” from the array.
09:09 Declare a number array and sort it.
09:12 Watch the video available at the following link.
09:15 It summarizes the "Spoken Tutorial" project.
09:19 If you do not have good bandwidth, you can download and watch it.
09:24 The "Spoken Tutorial" project team: Conducts workshops using spoken tutorials.
09:30 Gives certificates to those who pass an online test.
09:34 For more details, please write to: contact at spoken hyphen tutorial dot org.
09:40 "Spoken Tutorial" project is a part of the "Talk to a Teacher" project.
09:44 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
09:51 More information on this mission is available at: spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
10:02 Hope you enjoyed this Perl tutorial.
10:04 This is Amol, signing off.
10:06 Thanks for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Sandhya.np14

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