Difference between revisions of "PERL/C3/Referencing-and-Dereferencing/English-timed"

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(Created page with " {| Border = 1 | <center>''' Time '''</center> | <center>'''Narration'''</center> |- | 00:01 | Welcome to the''' Spoken Tutorial''' on''' Referencing and Dereferencing in...")
 
 
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|-
 
|-
 
| 00:07
 
| 00:07
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|  In this tutorial we will learn about
+
|  In this tutorial, we will learn about:
−
* '''Scalar References'''
+
'''Scalar References'''
−
* '''Array References'''
+
'''Array References'''
−
* '''Hash References'''  
+
'''Hash References'''  
−
* '''Dereferences''' and
+
'''Dereferences''' and
−
* How to add, remove, access '''elements''' of '''array/hash references'''
+
How to add, remove, access '''elements''' of '''array/hash references'''.
  
 
|-
 
|-
 
|  00:22
 
|  00:22
−
|  For this tutorial, I am using
+
|  For this tutorial, I am using:
−
* '''Ubuntu Linux 12.04''' operating system
+
'''Ubuntu Linux 12.04''' operating system
−
* '''Perl 5.14.2'''
+
'''Perl 5.14.2'''
−
* '''gedit Text Editor'''
+
'''gedit Text Editor'''
  
 
|-
 
|-
 
|  00:33
 
|  00:33
−
|You can use any text editor of your choice.
+
|You can use any text-editor of your choice.
  
 
|-
 
|-
 
|  00:37
 
|  00:37
−
|  You should have working knowledge of
+
|  You should have working knowledge of:
−
* '''Perl''' programming
+
'''Perl''' programming
−
* '''Array functions''' and
+
'''Array functions''' and
−
* '''Hash functions'''.
+
'''Hash functions'''.
  
 
|-
 
|-
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|-
 
|-
 
|  00:49
 
|  00:49
−
|  What is''' References'''?
+
|  What is a''' Reference'''?
  
 
|-
 
|-
 
|  00:51
 
|  00:51
−
|A''' reference''' is a '''pointer''' or an '''address''' to '''a variable, array, hash''' or a '''subroutine'''.
+
|A''' reference''' is a '''pointer''' or an '''address''' to a '''variable, array, hash''' or a '''subroutine'''.
  
 
|-
 
|-
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|-
 
|-
 
| 01:05
 
| 01:05
−
|  '''Reference''' will improve the performance of '''Perl''' code when you pass or return large data structures.
+
|  '''Reference''' will improve the performance of '''Perl''' code when you pass or return large data-structures.
  
 
|-
 
|-
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|-
 
|-
 
| 01:25
 
| 01:25
−
|  We can create a''' reference''' for any '''variable, subroutine''' or value, by putting a '''backslash (\)''' in front of it.
+
|  We can create a''' reference''' for any '''variable, subroutine''' or '''value''', by putting a '''backslash (\)''' in front of it.
  
 
|-
 
|-
 
|  01:33
 
|  01:33
−
|A''' scalar variable''' is''' referenced''' by '''backslash''' and '''dollar sign''' ($) as shown here.
+
|A''' scalar variable''' is''' reference'''d by backslash and dollar sign ($) as shown here.
  
 
|-
 
|-
 
|  01:39
 
|  01:39
−
|An''' array variable''' is''' referenced''' by '''backslash''' and '''at the rate(@)''' symbol.
+
|An''' array variable''' is''' reference'''d by backslash and '''at the rate(@)''' symbol.
  
 
|-
 
|-
 
|  01:45
 
|  01:45
−
|A''' hash variable''' is''' referenced''' by '''backslash''' and '''percentage(%)''' symbol as shown in the example here.
+
|A''' hash variable''' is''' reference'''d by backslash and '''percentage(%)''' symbol as shown in the example here.
  
 
|-
 
|-
 
|  01:53
 
|  01:53
−
| what is '''dereference'''?
+
| what is '''dereference'''?
  
 
|-
 
|-
 
|  01:55
 
|  01:55
−
|When a '''reference''' is''' dereferenced''', the actual value is returned.
+
|When a '''reference''' is''' dereference'''d, the actual value is returned.
  
 
|-
 
|-
 
|  02:00
 
|  02:00
−
|'''Dereference''' is done by enclosing the''' reference''' variable within curly brackets.
+
|'''Dereference''' is done by enclosing the''' reference''' variable within curly brackets
  
 
|-
 
|-
 
|  02:06
 
|  02:06
−
|And preceding the left curly bracket with a character denoting the type of''' reference''' it is.
+
|and preceding the left curly bracket with a character denoting the type of''' reference''' it is.
  
 
|-
 
|-
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|-
 
|-
 
|  02:16
 
|  02:16
−
| A''' scalar variable''' is dereferenced by '''dollar sign ($)''' and curly brackets.
+
| A''' scalar''' variable is dereferenced by dollar sign ($) and curly brackets.
  
 
|-
 
|-
 
|  02:21
 
|  02:21
−
|An''' array variable''' is dereferenced by '''at the rate (@)''' symbol and curly brackets.
+
|An''' array''' variable is dereferenced by '''at the rate (@)''' symbol and curly brackets.
  
 
|-
 
|-
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|-
 
|-
 
|  02:38
 
|  02:38
−
|  Let me open a sample program in''' gedit Text editor.'''
+
|  Let me open a sample program in ''''gedit' Text editor.'''
  
 
|-
 
|-
 
| 02:43
 
| 02:43
−
|  Open the '''terminal''' and type''' gedit scalarRef dot pl ampersand''' and press '''Enter'''.
+
|  Open the '''terminal''' and type: '''gedit scalarRef dot pl ampersand''' and press '''Enter'''.
  
 
|-
 
|-
 
| 02:50
 
| 02:50
−
|  Type the following code as displayed on the screen
+
|  Type the following code as displayed on the screen.
  
 
|-
 
|-
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|-
 
|-
 
|  03:03
 
|  03:03
−
|As mentioned earlier, a '''scalar variable''' is''' referenced''' by '''backslash''' and '''dollar sign ($)'''
+
|As mentioned earlier, a scalar variable is''' reference'''d by backslash and dollar sign ($).
  
 
|-
 
|-
 
|  03:10
 
|  03:10
−
|This line will print '''memory address''' of the '''variable''' that is created as''' reference'''.
+
|This line will print '''memory address''' of the variable that is created as''' reference'''.
  
 
|-
 
|-
 
|  03:16
 
|  03:16
−
|To print the actual value, the '''variable''' is''' dereferenced''' by curly brackets preceded by '''$'''.
+
|To print the actual value, the '''variable''' is''' dereference'''d by curly brackets preceded by '$'.
  
 
|-
 
|-
 
|  03:23
 
|  03:23
−
|Here'''ref()''' function will return the''' reference''' type such as '''scalar''' or '''array''' or '''hash'''.
+
|Here, '''ref()''' function will return the''' reference''' type such as '''scalar''' or '''array''' or '''hash'''.
  
 
|-
 
|-
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|-
 
|-
 
|  03:36
 
|  03:36
−
|  Switch to the '''terminal''' and type '''perl scalarRef dot pl''' and press''' Enter'''.
+
|  Switch to the '''terminal''' and type: '''perl scalarRef dot pl''' and press''' Enter'''.
  
 
|-
 
|-
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|-
 
|-
 
|  03:46
 
|  03:46
−
|First line shows the memory address where the value 10 is stored.
+
|First line shows the '''memory address''' where the value 10 is stored.
  
 
|-
 
|-
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|-
 
|-
 
|  03:55
 
|  03:55
−
|'''Ref() function '''returns ''''Scalar'''' as output.
+
|'''Ref()''' function returns "SCALAR" as output.
  
 
|-
 
|-
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|-
 
|-
 
|  04:07
 
|  04:07
−
|  I already have a sample program. Let me open it in''' gedit Text editor.'''
+
|  I already have a sample program. Let me open it in 'gedit' Text editor.
  
 
|-
 
|-
 
| 04:13
 
| 04:13
−
|  In the '''terminal''', type''' gedit arrayRef dot pl ampersand''' and press '''Enter'''.
+
|  In the '''terminal''', type: '''gedit arrayRef dot pl ampersand''' and press '''Enter'''.
  
 
|-
 
|-
 
| 04:20
 
| 04:20
−
|  Type the following code as displayed on the screen in the '''arrayRef dot pl''' file.
+
|  Type the following code as displayed on the screen, in the '''arrayRef dot pl''' file.
  
 
|-
 
|-
Line 209: Line 209:
 
|-
 
|-
 
|  04:28
 
|  04:28
−
|Here, in the first line, I have declared an '''array @color''' and initialised it with three values.
+
|Here, in the first line, I have declared an array '''@color''' and initialized it with three values.
  
 
|-
 
|-
 
|  04:35
 
|  04:35
−
|It is''' referenced''' with '''backslash @color''' which is the '''array name''' and assigned to''' $colorRef.'''
+
|It is '''reference'''d with '''backslash @color''' which is the array name and assigned to''' $colorRef.'''
  
 
|-
 
|-
 
|  04:42
 
|  04:42
−
|The '''print''' statement will print the''' reference''' value and the''' dereferenced''' value.
+
|The '''print''' statement will print the''' reference''' value and the''' dereference'''d value.
  
 
|-
 
|-
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|-
 
|-
 
| 04:53
 
| 04:53
−
|  Switch back to the '''terminal''' and type '''perl arrayRef dot pl''' and press''' Enter'''.
+
|  Switch back to the '''terminal''' and type: '''perl arrayRef dot pl''' and press''' Enter'''.
  
 
|-
 
|-
 
| 05:00
 
| 05:00
−
|  The output is displayed as shown here
+
|  The output is displayed as shown here.
  
 
|-
 
|-
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|-
 
|-
 
|  05:10
 
|  05:10
−
|The second line shows the actual value that is''' dereferenced'''.
+
|The second line shows the actual value that is''' dereference'''d.
  
 
|-
 
|-
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|-
 
|-
 
|  05:24
 
|  05:24
−
|I have changed the existing program to show the '''direct reference''' for an '''array'''.
+
|I have changed the existing program to show the '''direct reference''' for an array.
  
 
|-
 
|-
 
|  05:29
 
|  05:29
−
|  You can create a '''direct reference''' for an''' array''' by using square brackets<nowiki> [] </nowiki>as shown.
+
|  You can create a '''direct reference''' for an array by using square brackets<nowiki> [] </nowiki>as shown.
  
 
|-
 
|-
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|-
 
|-
 
|  05:39
 
|  05:39
−
|'''print''' statement will print ''''Green'''' as output.
+
|'''print''' statement will print "Green" as output.
  
 
|-
 
|-
 
|  05:43
 
|  05:43
−
|Here the '''print''' statement takes the value of index<nowiki>[1]. </nowiki>i.e '''Green''' in our program.
+
|Here, the '''print''' statement takes the value of index<nowiki>[1]. </nowiki> i.e 'Green' in our program.
  
 
|-
 
|-
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|-
 
|-
 
|  05:54
 
|  05:54
−
|  Switch back to the '''terminal''' and type '''perl arrayRef dot pl''' and press''' Enter''' to execute.
+
|  Switch back to the '''terminal''' and type: '''perl arrayRef dot pl''' and press''' Enter''' to execute.
  
 
|-
 
|-
 
|  06:03
 
|  06:03
−
|  I’ll show an example on how to use the direct hash reference in the same code file.
+
|  I’ll show an example on how to use the '''direct hash reference''' in the same code file.
 
So, let’s switch to '''gedit'''.
 
So, let’s switch to '''gedit'''.
  
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|-
 
|-
 
|  06:18
 
|  06:18
−
| Use '''arrow operator (->)''' to dereference it. '''“Name”''' is the '''hash key'''.
+
| Use '''arrow operator (->)''' to dereference it. “Name” is the '''hash key'''.
  
 
|-
 
|-
 
|  06:24
 
|  06:24
−
| On executing this block of code, both the '''print''' statements will print ''''Sunil'''' as output.
+
| On executing this block of code, both the '''print''' statements will print "Sunil" as output.
  
 
|-
 
|-
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|-
 
|-
 
|  06:39
 
|  06:39
−
|  I already have a sample program. Let me open it in''' gedit Text editor'''
+
|  I already have a sample program. Let me open it in''' gedit''' text-editor.
  
 
|-
 
|-
 
|  06:45
 
|  06:45
−
|  Open the''' terminal''' and type''' gedit arrayRefadd dot pl ampersand '''and press''' Enter'''
+
|  Open the''' terminal''' and type:''' gedit arrayRefadd dot pl ampersand '''and press''' Enter'''.
  
 
|-
 
|-
 
|  06:54
 
|  06:54
−
|  '''arrayRefadd.pl''' file is now open in''' gedit.''' Type the code as shown here in your file.
+
|  'arrayRefadd.pl' file is now open in''' gedit.''' Type the code as shown here, in your file.
  
 
|-
 
|-
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|-
 
|-
 
|  07:06
 
|  07:06
−
| We have '''referenced''' an '''array''' with '''backslash @numarray''' and assigned to''' $ref.'''
+
| We have '''reference'''d an array with '''backslash @numarray''' and assigned to''' $ref.'''
  
 
|-
 
|-
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|-
 
|-
 
|  07:19
 
|  07:19
−
| We need to use the '''array index''' in square brackets<nowiki> “[ ]” </nowiki>to access the particular value. And an '''arrow operator (“->”)''' to''' dereference''' it.
+
| We need to use the '''array index''' in square brackets<nowiki> “[ ]” </nowiki> to access the particular value and an '''arrow operator (“->”)''' to''' dereference''' it.
  
 
|-
 
|-
 
|  07:28
 
|  07:28
−
| The '''print''' statement will print the value of index<nowiki>[0]</nowiki>
+
| The '''print''' statement will print the value of index <nowiki>[0]</nowiki>.
  
 
|-
 
|-
 
|  07:32
 
|  07:32
−
| '''Push function '''adds '''elements''' at the last position of an''' array reference.'''
+
| '''push()''' function adds '''elements''' at the last position of an''' array reference.'''
−
In our case 5,6,7 is added to at the end of the existing array 1,2,3,4.
+
In our case, 5, 6, 7 are added to the end of the existing array 1, 2, 3, 4.
  
 
|-
 
|-
 
|  07:47
 
|  07:47
−
| This '''print''' statement shows the output after adding to the''' array reference.'''
+
| This '''print''' statement shows the output, after adding to the''' array reference.'''
  
 
|-
 
|-
 
|  07:53
 
|  07:53
−
| '''Pop function '''removes an element from the last position of an''' array reference'''
+
| '''pop()''' function removes an '''element''' from the last position of an''' array reference'''.
  
 
|-
 
|-
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|-
 
|-
 
|  08:14
 
|  08:14
−
|  Switch back to the '''terminal''' and type '''perl arrayRefadd dot pl''' and press''' Enter'''.
+
|  Switch back to the '''terminal''' and type: '''perl arrayRefadd dot pl''' and press''' Enter'''.
  
 
|-
 
|-
 
| 08:22
 
| 08:22
−
|  The output is displayed as shown here
+
|  The output is displayed as shown here.
  
 
|-
 
|-
 
|  08:26
 
|  08:26
−
|  Now let us see another sample program to add, remove, and access '''elements''' of''' hash reference.'''
+
|  Now, let us see another sample program to add, remove, and access '''elements''' of''' hash reference.'''
  
 
|-
 
|-
 
|  08:34
 
|  08:34
−
|  In the '''terminal''' type '''gedit hashRefadd dot pl ampersand'''  and press '''Enter'''.
+
|  On the '''terminal''', type: '''gedit hashRefadd dot pl ampersand'''  and press '''Enter'''.
  
 
|-
 
|-
 
|  08:42
 
|  08:42
−
|  This will open the file''' hashRefadd.pl''' in''' gedit'''.
+
|  This will open the file 'hashRefadd.pl' in''' gedit'''.
  
 
|-
 
|-
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|-
 
|-
 
|  09:09
 
|  09:09
−
| I am using the '''“keys” built-in function''' to loop through the '''keys''' of the '''hash'''.
+
| I am using the '''“keys” built-in function''' to loop through the keys of the hash.
  
 
|-
 
|-
 
|  09:15
 
|  09:15
−
| '''print''' statement will print each element of the '''hash'''.
+
| '''print''' statement will print each element of the hash.
−
 
+
  
 
|-
 
|-
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|-
 
|-
 
| 09:32
 
| 09:32
−
|  Switch to '''terminal''' and type '''perl hashRefadd dot pl''' and press''' Enter '''to see the output.
+
|  Switch to '''terminal''' and type: '''perl hashRefadd dot pl''' and press''' Enter '''to see the output.
  
 
|-
 
|-
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|09:57
 
|09:57
 
| In this tutorial, we learnt about:
 
| In this tutorial, we learnt about:
−
 
+
'''Scalar References'''
−
* '''Scalar References'''
+
'''Array References'''
−
* '''Array References'''
+
'''Hash References'''  
−
* '''Hash References'''  
+
'''Dereferences''' and
−
* '''Dereferences''' and
+
How to add, remove, access '''elements''' of '''array/hash references''' with examples.
−
* How to add, remove, access '''elements''' of '''array/hash references''' with examples.
+
  
 
|-
 
|-
 
|  10:14
 
|  10:14
−
| Here is an assignment for you.
+
| Here is an assignment for you. Add new keys “Saturday” and “Sunday” in hash '''weektemp''', in our''' hashRefadd dot pl file.'''
−
Add new keys “'''Saturday'''” and “'''Sunday'''” in hash '''weektemp''' in our''' hashRefadd dot pl file.'''
+
  
 
|-
 
|-
 
| 10:24
 
| 10:24
−
| Delete key “'''Saturday'''” at the end.
+
| Delete key “Saturday” at the end.
  
 
|-
 
|-
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|-
 
|-
 
|  10:30
 
|  10:30
−
| Save and execute the program. Now check the result.
+
| '''Save''' and '''execute''' the program. Now check the result.
  
 
|-
 
|-
 
|  10:35
 
|  10:35
−
| The video at the following link summarises the Spoken Tutorial project.
+
| The video at the following link summarizes the '''Spoken Tutorial''' project.Please download and watch it.
−
Please download and watch it
+
  
 
|-
 
|-
 
| 10:42
 
| 10:42
−
| We conduct workshops and give certificates for those who pass our online tests.
+
| We conduct workshops and give certificates for those who pass our online tests. For more details, please write to us.
−
For more details, please write to us.
+
  
 
|-
 
|-
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|-
 
|-
 
|  11:02
 
|  11:02
−
|  This is Nirmala Venkat from IIT Bombay, signing off. Thanks for watching.
+
|  This is Nirmala Venkat from '''IIT Bombay''', signing off. Thanks for watching.
  
 
|}
 
|}

Latest revision as of 18:13, 20 February 2017

Time
Narration
00:01 Welcome to the Spoken Tutorial on Referencing and Dereferencing in Perl.
00:07 In this tutorial, we will learn about:

Scalar References Array References Hash References Dereferences and How to add, remove, access elements of array/hash references.

00:22 For this tutorial, I am using:

Ubuntu Linux 12.04 operating system Perl 5.14.2 gedit Text Editor

00:33 You can use any text-editor of your choice.
00:37 You should have working knowledge of:

Perl programming Array functions and Hash functions.

00:43 If not, then go through the relevant Perl tutorials on this website.
00:49 What is a Reference?
00:51 A reference is a pointer or an address to a variable, array, hash or a subroutine.
00:58 It does not contain data directly.
01:01 Reference is an easy, compact scalar value.
01:05 Reference will improve the performance of Perl code when you pass or return large data-structures.
01:12 It saves memory as it passes a reference to a subroutine rather than passing a value.
01:18 Easy to manage complicated Perl data structures.
01:22 Let us learn how to create a reference.
01:25 We can create a reference for any variable, subroutine or value, by putting a backslash (\) in front of it.
01:33 A scalar variable is referenced by backslash and dollar sign ($) as shown here.
01:39 An array variable is referenced by backslash and at the rate(@) symbol.
01:45 A hash variable is referenced by backslash and percentage(%) symbol as shown in the example here.
01:53 what is dereference?
01:55 When a reference is dereferenced, the actual value is returned.
02:00 Dereference is done by enclosing the reference variable within curly brackets
02:06 and preceding the left curly bracket with a character denoting the type of reference it is.
02:12 Let us see how to dereference variables.
02:16 A scalar variable is dereferenced by dollar sign ($) and curly brackets.
02:21 An array variable is dereferenced by at the rate (@) symbol and curly brackets.
02:27 A hash variable is dereferenced by percentage(%) symbol and curly brackets.
02:33 Let us see a simple program for Scalar reference and dereference.
02:38 Let me open a sample program in 'gedit' Text editor.
02:43 Open the terminal and type: gedit scalarRef dot pl ampersand and press Enter.
02:50 Type the following code as displayed on the screen.
02:55 Let me explain the code.
02:57 First line declares a scalar variable '$a' and initialized to 10.
03:03 As mentioned earlier, a scalar variable is referenced by backslash and dollar sign ($).
03:10 This line will print memory address of the variable that is created as reference.
03:16 To print the actual value, the variable is dereferenced by curly brackets preceded by '$'.
03:23 Here, ref() function will return the reference type such as scalar or array or hash.
03:30 Now, press Ctrl+S to save the file.
03:34 Let us execute the program.
03:36 Switch to the terminal and type: perl scalarRef dot pl and press Enter.
03:43 The output is displayed as shown.
03:46 First line shows the memory address where the value 10 is stored.
03:51 The second line returns the actual value 10.
03:55 Ref() function returns "SCALAR" as output.
03:59 Next, let us understand how to create a reference and dereference array by using a sample program.
04:07 I already have a sample program. Let me open it in 'gedit' Text editor.
04:13 In the terminal, type: gedit arrayRef dot pl ampersand and press Enter.
04:20 Type the following code as displayed on the screen, in the arrayRef dot pl file.
04:26 Let me explain the code now.
04:28 Here, in the first line, I have declared an array @color and initialized it with three values.
04:35 It is referenced with backslash @color which is the array name and assigned to $colorRef.
04:42 The print statement will print the reference value and the dereferenced value.
04:47 Now, press Ctrl+S to save the file.
04:51 Let us execute the program.
04:53 Switch back to the terminal and type: perl arrayRef dot pl and press Enter.
05:00 The output is displayed as shown here.
05:04 The first line shows the output of the memory address of the variable that is created as reference.
05:10 The second line shows the actual value that is dereferenced.
05:16 Next, we will see how to declare direct reference for an array.
05:21 Let’s come back to our program.
05:24 I have changed the existing program to show the direct reference for an array.
05:29 You can create a direct reference for an array by using square brackets [] as shown.
05:35 Use arrow operator (->) to dereference.
05:39 print statement will print "Green" as output.
05:43 Here, the print statement takes the value of index[1]. i.e 'Green' in our program.
05:50 Press Ctrl+S to save the file.
05:54 Switch back to the terminal and type: perl arrayRef dot pl and press Enter to execute.
06:03 I’ll show an example on how to use the direct hash reference in the same code file.

So, let’s switch to gedit.

06:11 You can create a direct reference to hash by using curly brackets {} as shown here.
06:18 Use arrow operator (->) to dereference it. “Name” is the hash key.
06:24 On executing this block of code, both the print statements will print "Sunil" as output.
06:31 Next we will see how to add, remove, access elements to array reference with a sample program.
06:39 I already have a sample program. Let me open it in gedit text-editor.
06:45 Open the terminal and type: gedit arrayRefadd dot pl ampersand and press Enter.
06:54 'arrayRefadd.pl' file is now open in gedit. Type the code as shown here, in your file.
07:02 The first line initializes an array.
07:06 We have referenced an array with backslash @numarray and assigned to $ref.
07:13 Now, we will see how to access a particular element from the array reference.
07:19 We need to use the array index in square brackets “[ ]” to access the particular value and an arrow operator (“->”) to dereference it.
07:28 The print statement will print the value of index [0].
07:32 push() function adds elements at the last position of an array reference.

In our case, 5, 6, 7 are added to the end of the existing array 1, 2, 3, 4.

07:47 This print statement shows the output, after adding to the array reference.
07:53 pop() function removes an element from the last position of an array reference.
07:58 In our example, 7 will be removed from the existing array reference.
08:03 print statement shows the output after deleting from the array reference.
08:08 Now, press Ctrl+S to save the file.
08:11 Let us execute the program.
08:14 Switch back to the terminal and type: perl arrayRefadd dot pl and press Enter.
08:22 The output is displayed as shown here.
08:26 Now, let us see another sample program to add, remove, and access elements of hash reference.
08:34 On the terminal, type: gedit hashRefadd dot pl ampersand and press Enter.
08:42 This will open the file 'hashRefadd.pl' in gedit.
08:47 Let me explain the sample program.
08:50 I have declared a direct hash reference that can be stored in a scalar variable $weektemp.
08:57 I have used curly brackets to represent the hash reference and the arrow operator to dereference.
09:04 This code stores the temperature values from Monday to Friday.
09:09 I am using the “keys” built-in function to loop through the keys of the hash.
09:15 print statement will print each element of the hash.
09:19 We can access the particular value of an element as shown here.
09:25 print statement will print the temperature on Monday.
09:29 Now, save the file.
09:32 Switch to terminal and type: perl hashRefadd dot pl and press Enter to see the output.
09:41 The hash keys and hash values are stored in a random order.
09:46 The displayed output is not related to the order in which they were added.
09:52 With this, we come to the end of this tutorial. Let us summarize.
09:57 In this tutorial, we learnt about:

Scalar References Array References Hash References Dereferences and How to add, remove, access elements of array/hash references with examples.

10:14 Here is an assignment for you. Add new keys “Saturday” and “Sunday” in hash weektemp, in our hashRefadd dot pl file.
10:24 Delete key “Saturday” at the end.
10:27 Print hash weektemp.
10:30 Save and execute the program. Now check the result.
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10:51 Spoken Tutorial project is funded by NMEICT, MHRD, Government of India.

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11:02 This is Nirmala Venkat from IIT Bombay, signing off. Thanks for watching.

Contributors and Content Editors

PoojaMoolya, Sandhya.np14

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