Difference between revisions of "PERL/C2/Conditional-statements/English-timed"

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|* '''if ''' statement and  
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|'''if ''' statement and  
  
 
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|* ''' if-else''' statement in Perl.  
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|''' if-else''' statement in Perl.  I am using '''Ubuntu Linux 12.04''' operating system and '''Perl 5.14.2'''.
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| I am using '''Ubuntu Linux 12.04''' operating system and '''Perl 5.14.2'''.
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|* '''if'''
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| '''if''', '''if-else '''
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|* '''if-else '''
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|* '''if-elsif-else''' and  
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| '''if-elsif-else''' and  
 
   
 
   
 
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|00:53
 
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|* '''switch '''.
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|'''switch '''.In this tutorial, we will cover '''if '''and '''if-else''' statements.  
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|In this tutorial, we will cover '''if '''and '''if-else''' statements.  
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|'''Enter'''
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|'''Enter'''.Piece of code semicolon to be executed when the condition is true   
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|piece of code semicolon to be executed when the condition is true   
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| Now let us look at an example of '''if ''' statement.  
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| Now, let us look at an example of '''if ''' statement.  
 
   
 
   
 
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| and press '''Enter. '''
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|and press '''Enter. '''
 
   
 
   
 
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| As there is no compilation or syntax error, we will execute the Perl script by typing:  
 
| As there is no compilation or syntax error, we will execute the Perl script by typing:  
 
   
 
   
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|'''print''' space double quotes '''I am inside if statement''' slash '''n''' close double quotes space '''if''' space open bracket '''dollar count space equal to equal to space 5''' close bracket semicolon.
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|'''print''' space double quotes '''I am inside if statement''' backslash '''n''' close double quotes space '''if''' space open bracket '''dollar count space equal to equal to space 5''' close bracket semicolon.
  
 
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|Now, let us look at '''if-else''' statement.  
 
|Now, let us look at '''if-else''' statement.  
 
   
 
   
 
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|This statement is used when user wants to execute  
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|This statement is used when user wants to execute-
 
   
 
   
 
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|one piece of code when the condition is '''true''' and  
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|one piece of code when the condition is '''True''' and  
 
   
 
   
 
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| another piece of code when the condition is '''false'''.  
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| another piece of code when the condition is '''False'''.  
  
 
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|04:13
 
| The syntax for '''if-else''' condition is as follows:  
 
| The syntax for '''if-else''' condition is as follows:  
  
 
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| '''if ''' space open bracket '''condition''' close bracket space open curly bracket Press '''Enter'''.  
 
| '''if ''' space open bracket '''condition''' close bracket space open curly bracket Press '''Enter'''.  
 
   
 
   
 
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|piece of code semicolon  
 
|piece of code semicolon  
  
 
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| to be executed when '''if''' condition is '''true''',  
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| to be executed when '''if''' condition is '''true''',  
 
   
 
   
 
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| Assign 4 to '''count''' variable. Then at the end of the '''if''' block, type: space  
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| Assign 4 to '''count''' variable. Then at the end of the '''if''' block, type: space  
  
 
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| ''' else '''
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|''' else '''
 
   
 
   
 
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|'''print''' space double quotes '''I am inside else statement slash n'''  double quotes complete semicolon  
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|'''print''' space double quotes '''I am inside else statement backslash n'''  double quotes complete semicolon.
 
   
 
   
 
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| Now switch to terminal
 
| Now switch to terminal
 
   
 
   
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| Now, press '''Enter'''.
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|Now, press '''Enter'''.
  
 
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| The following line will be displayed on the terminal:  
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|The following line will be displayed on the terminal:  
 
   
 
   
 
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| "conditionalBlocks.pl syntax OK"
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|"conditionalBlocks.pl syntax OK"
  
 
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|As there is no compilation or syntax error, we will now execute the '''Perl script'''.  
 
|As there is no compilation or syntax error, we will now execute the '''Perl script'''.  
 
   
 
   
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| and press '''Enter'''.
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|and press '''Enter'''.
  
 
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| The following output will be shown on terminal.   
 
| The following output will be shown on terminal.   
  
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|'''if''' and  
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|'''if''' and '''if-else''' conditional statements in Perl  
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|'''if-else''' conditional statements in Perl  
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| The Spoken Tutorial project Team:  
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| The Spoken Tutorial project team:  
  
 
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| 07:22
 
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| Conducts workshops using spoken tutorials.
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|Conducts workshops using spoken tutorials.
 
   
 
   
 
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|07:26
 
|07:26
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|Gives certificates to those who pass an online test.
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| Gives certificates to those who pass an online test.
 
   
 
   
 
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Latest revision as of 15:24, 10 March 2017

Time Narration
00:01 Welcome to the spoken tutorial on if and if-else conditional statements in PERL.
00:07 In this tutorial, we will learn about:
00:09 if statement and
00:11 if-else statement in Perl. I am using Ubuntu Linux 12.04 operating system and Perl 5.14.2.
00:20 I will also be using the gedit Text Editor.
00:24 You can use any text editor of your choice.
00:28 You should have basic knowledge of variables and comments in Perl.
00:33 Knowledge of for, foreach , while and do-while loops in Perl will be an added advantage.
00:40 Please go through the relevant spoken tutorials on the Spoken Tutorial website.
00:45 Perl provides the following conditional statements:
00:49 if, if-else
00:51 if-elsif-else and
00:53 switch .In this tutorial, we will cover if and if-else statements.
00:59 if statement in Perl can be used
01:01 to execute a piece of code only when a specified condition is satisfied.
01:07 The syntax of if conditional statement is as follows:
01:11 if space open bracket condition close bracket space open curly bracket
01:19 Enter.Piece of code semicolon to be executed when the condition is true
01:25 Enter close curly bracket.
01:29 The code inside the if statement will be executed only when the condition is true.
01:36 Now, let us look at an example of if statement.
01:40 Open the Terminal and type:
01:43 gedit conditionalBlocks dot pl space &(ampersand )
01:49 and press Enter.
01:52 This will open the conditionalBlocks.pl file in gedit.
01:57 Type the following piece of code as displayed on the screen.
02:02 Here we have specified a condition for if which checks the value of variable count.
02:09 Note the equal to equal to sign here. This is the comparison operator.
02:15 The condition $count equal to equal to 5 is checked against the value of variable count.
02:23 When it is equal to 5, the code within the if block will get executed.
02:28 Now, press ctrl+s to save the file.
02:32 Then switch to the terminal.
02:36 Make sure that you are in the directory in which you have saved your file.
02:41 Type the following to check for any compilation or syntax error:
02:46 perl hyphen c conditionalBlocks dot pl
02:53 and press Enter.
02:55 The following line will be displayed on the terminal window:
02:59 "conditionalBlocks.pl syntax OK".
03:04 As there is no compilation or syntax error, we will execute the Perl script by typing:
03:10 perl conditionalBlocks dot pl
03:14 and press Enter.
03:16 The following output will be shown on terminal.
03:19 "I am inside if statement".
03:23 Switch back to gedit.
03:26 Alternately, we can write the above if statement as:
03:31 print space double quotes I am inside if statement backslash n close double quotes space if space open bracket dollar count space equal to equal to space 5 close bracket semicolon.
03:57 Now, let us look at if-else statement.
04:01 This statement is used when user wants to execute-
04:06 one piece of code when the condition is True and
04:09 another piece of code when the condition is False.
04:13 The syntax for if-else condition is as follows:
04:17 if space open bracket condition close bracket space open curly bracket Press Enter.
04:27 piece of code semicolon
04:29 to be executed when if condition is true,
04:32 press Enter
04:34 close curly bracket space else space open curly bracket Enter
04:41 another piece of code semicolon
04:43 to be executed when if condition is false
04:47 press Enter close curly bracket.
04:51 Now, again go to the conditionalBlocks.pl file which we have already created in gedit.
04:58 Assign 4 to count variable. Then at the end of the if block, type: space
05:07 else
05:09 space open curly bracket press Enter
05:14 print space double quotes I am inside else statement backslash n double quotes complete semicolon.
05:30 Press Enter and close curly bracket.
05:34 Here, 4 is assigned to variable $count.
05:38 As the value of count variable does not match 5,
05:43 the code within the if block will not get executed.
05:47 Instead, the code within the else block will get executed.
05:52 Now press Ctrl+S to save the file.
05:56 Now switch to terminal
05:59 and type: perl hyphen c conditionalBlocks dot pl to check for any compilation or syntax error.
06:11 Now, press Enter.
06:13 The following line will be displayed on the terminal:
06:17 "conditionalBlocks.pl syntax OK"
06:20 As there is no compilation or syntax error, we will now execute the Perl script.
06:27 Type: perl conditionalBlocks dot pl
06:33 and press Enter.
06:35 The following output will be shown on terminal.
06:39 "I am inside else statement".
06:44 Let us summarize.
06:46 In this tutorial, we have learnt:
06:49 if and if-else conditional statements in Perl
06:53 using sample programs.
06:55 Here is an assignment for you:
06:57 Print “It is an open source language”
07:01 when the variable declared has value 'Perl'
07:04 otherwise, print “It's a proprietary language”.
07:08 Watch the video available at the following link.
07:11 It summarizes the Spoken Tutorial project.
07:15 If you do not have good bandwidth, you can download and watch it.
07:20 The Spoken Tutorial project team:
07:22 Conducts workshops using spoken tutorials.
07:26 Gives certificates to those who pass an online test.
07:31 For more details, please write to contact at spoken hyphen tutorial dot org.
07:37 "Spoken Tutorial" project is a part of the "Talk to a Teacher" project.
07:42 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
07:50 More information on this mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
08:00 Hope you enjoyed this Perl tutorial.
08:04 This is Amol Brahmankar, signing off.
08:06 Thanks for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Sandhya.np14

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