View source for PERL/C2/for-for-each-loops/English-timed

{| border=1
|  '''Time'''
| '''Narration'''
 
|-
| 00:01
|Welcome to the spoken tutorial on '''for '''and''' foreach Loops''' in '''Perl'''.
 
|-
| 00:06
| In this tutorial, we will learn about: '''for''' loop in '''Perl '''and
|-
|00:11
|'''foreach''' loop in '''Perl'''.
 
|-
|00:13
| I am using '''Ubuntu Linux 12.04''' operating system and '''Perl 5.14.2'''.
 
|-
|00:21
|I will also be using the '''gedit '''Text Editor.
 
|-
|00:25
|You can use any text editor of your choice.
 
|-
| 00:29
| You should have basic knowledge of variables and comments in''' Perl.'''
 
|-
|00:33
|If not, please go through the relevant spoken tutorials on the '''spoken tutorial '''website.
 
|-
|00:40
|  '''Perl''' provides a mechanism by which we can check a condition repeatedly for various values. This is done using '''loops'''.
 
|-
| 00:49
|  There are various types of loops in Perl:
 
|-
|00:52
|'''for loop''', '''foreach loop'''
 
|-
|00:54
|'''while loop''' and '''do-while loop'''.

|-
|00:56
|In this tutorial, we will cover '''for''' and '''foreach loop'''.
 
|-
|01:01
| '''for''' loop in '''Perl''' can be used to execute a piece of code for a certain number of times.
 
|-
| 01:07
| The syntax of '''for loop''' is as follows:
|-
|01:10
|'''for space open bracket variable initialization semicolon condition semicolon increment
|-
|01:20
|close bracket''', press '''Enter'''.

|-
|01:22
|Open curly brackets,
 
|-
|01:24
|piece of code to be executed multiple times,

|-
|01:28
|close curly brackets.
 
|-
|01:30
| Now let us look at an example of a '''for '''loop.
 
|-
| 01:33
| Open the '''Terminal''' and type: '''gedit forLoop.pl space & (ampersand)'''
 
|-
|01:42
|and press''' Enter'''. This will open the '''forLoop.pl''' file in '''gedit'''.
 
|-
|01:48
| Type the following piece of code: '''hash exclamation mark slash u s r slash bin slash perl'''
 
|-
|01:58
|press '''Enter'''.
 
|-
|02:00    
|'''for space open bracket dollar i equals to zero semicolon space dollar i less than or equal to four semicolon space dollar i plus plus close bracket'''
 
|-
|02:18
|space Open curly bracket  press '''Enter'''.
 
|-
|02:21
| Type: '''print space double quote Value of i colon <space> dollar i backslash n'''  double quote complete semicolon 
 
|-
|02:35
| and press '''Enter'''. Now close curly bracket.
 
|-
|02:39
|Press '''Ctrl+S''' to '''save''' the file.
 
|-
| 02:42    
| Let me explain what the '''for''' loop does.

|-
|02:46
|The variable '''i''' is initialized to zero.
 
|-
|02:50
|  Next, the condition is checked. 
 
|-
|02:53
|In this case, the condition is '''i less than or equal to 4'''.
 
|-
|02:59
|If this condition is true, the code within the curly bracket will be executed.
 
|-
| 03:05
|This means the first print statement  "Value of i colon 0"
 
|-
|03:11
|will be displayed on the terminal.
 
|-
|03:14
| After this, the variable 'i' is incremented by 1. 
 
|-
| 03:18
| And the '''for''' loop condition is checked once again.
 
|-
|03:23
|This loop will exit when the value of ' i' becomes greater than 4.
 
|-
|03:29
|In this case, the '''for''' loop will be executed for i = 0, 1, 2, 3, and 4.

|-
|03:38
|which is a total of 5 times.
 
|-
|03:41
|Now, switch to terminal.
 
|-
|03:44
|Type the following to check for any compilation or syntax error:
 
|-
|03:48
|'''perl hyphen c forLoop dot pl'''
 
|-
|03:54 
|and press''' Enter.'''
 
|-
|03:56
|Here it displays a message: 
 
|-
|03:58
|'''forLoop.pl syntax OK'''.
 
|-
|04:01
|So, we have no errors.
 
|-
|04:03
| Now, let us execute the '''Perl''' script by typing '''perl forLoop dot pl''' and press '''Enter.'''
 
|-
|04:11
|The following output will be shown on the terminal.
 
|-
|04:16
| Now, let us look at  '''foreach '''loop.
 
|-
| 04:19
| If we want to iterate a condition for an '''array''', we can make use of '''foreach '''loop.
 
|-
| 04:25
|  The syntax is: '''foreach space dollar variable space within brackets at the rate array ''' space 

|-
|04:35
|open curly bracket 
 
|-
|04:37
|'''perform action on each element of an  array ''' press '''Enter''',
 
|-
|04:42
|close the curly bracket.
 
|-
|04:44
|Please note: We'll cover array, array initialization and defining an array in subsequent tutorials.
 
|-
|04:52
|  Now let us look at an example of '''foreach''' loop.
 
|-
| 04:56
|  Open the Terminal and type: '''gedit foreachLoop dot pl space ampersand''' and press''' Enter'''.
 
|-
| 05:08
|  This will open the '''foreachLoop.pl''' file in '''gedit'''.
 
|-
|05:12
| Type the following piece of code:
|-
|05:15
|'''hash exclamation mark slash u s r slash bin slash perl''' and press '''Enter'''.
 
|-
|05:25
|'''at the rate myarray space equal to space open bracket ten comma twenty comma thirty close the bracket semicolon'''
 
|-
|05:39
|press '''Enter'''. 
 
|-
|05:41
|'''foreach space dollar var space open bracket at the rate myarray close the bracket space'''
|-
|05:52
|open curly bracket press '''Enter''' and type:
 
|-
|05:56
|'''print space double quotes Element of an array is colon dollar var backslash n'''  double quotes complete semicolon 

|-
|06:13
|press '''Enter''' and close the curly bracket.
 
|-
|06:17
|Press '''Ctrl+s''' to '''save''' the file.
 
|-
|  06:20
| Let me explain what this code does. An array '''myarray '''is declared. 
 
|-
|06:27
|It has 3 elements 10, 20 and 30.
 
|-
|  06:33
|  In each iteration of '''foreach''' loop, 'dollar var' ($var) will contain the single element of an array.
 
|-
|  06:40
|   '''foreach '''keyword will repeat this loop for each element of an array.
 
|-
| 06:47
|  That is, the code within the curly bracket will be executed for each '''myarray '''element.
 
|-
|  06:55
| '''Back-slash n''' (\n) will place the prompt on a new line.
 
|-
|  07:00
| This means, the first '''element''' 10 will be displayed on the terminal.

|-
|07:06
|Then 20 and so on, till all the elements are printed.
 
|-
|  07:12
|  This loop will exit after printing all the elements in '''myarray'''.
 
|-
|  07:17
| Now, switch to terminal and type the following to check for any compilation or syntax error.
 
|-
|07:24
|Type: '''perl hyphen c foreachLoop dot pl''' and press''' Enter.'''
 
|-
| 07:32
|  The following line will be shown on the terminal.
 
|-
| 07:36
|  There are no compilation or syntax errors.
 
|-
|07:38
|So, let us execute the '''Perl''' script.

|-
|07:41
|Type:  '''perl foreachLoop dot pl''' and press '''Enter'''.
 
|-
| 07:48
| The following output will be shown on the terminal.
|-
|  07:54
| So, that's it about '''for''' loop and '''foreach''' loop.
 
|-
|  07:57
| Let us summarize.
 
|-
|07:59
|In this tutorial, we have learnt -
 
|-
|08:02
|'''for''' loop and '''foreach''' loop in '''Perl'''
 
|-
|08:06
|using some sample programs. Here is an assignment for you -
 
|-
|08:10
| Declare a '''string''' as 'Spoken Tutorial' and 
|-
|08:13
| print it 5 times.
|-
|08:16
| Declare an array of colors as @colorArray = open bracket in single quote red comma white comma  blue close the bracket and 
|-
|08:32
| print the element of an array using '''foreach''' loop.
 
|-
|08:36
|Watch the video available at the following link.
 
|-
|08:40
|It summarizes the Spoken Tutorial project.
 
|-
|08:43
|If you do not have good bandwidth, you can download and watch it.
 
|-
| 08:48
|  The Spoken Tutorial Project Team:  Conducts workshops using spoken tutorials.
 
|-
|08:55
|Gives certificates to those who pass an online test.

|-
|08:59
|For more details, please write to contact at spoken hyphen tutorial dot org.
 
|-
| 09:07
|  "Spoken Tutorial" project is a part of the "Talk to a Teacher" project.
 
|-
|09:12
|It is supported by the National Mission on Education through ICT, MHRD, Government of India.
 
|-
|09:20
|More information on this mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
 
|-
| 09:31
|Hope you enjoyed this '''Perl''' tutorial. 
 
|-
|09:34
|This is Amol, signing off.

|-
|09:36
|Thanks for joining.
 
|}