Difference between revisions of "PERL/C2/Data-Structures/English-timed"

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|Welcome to the spoken tutorial on '''Data Structures''' in '''Perl'''

|Welcome to the spoken tutorial on '''Data Structures''' in '''Perl'''

|-

|-

| In this tutorial, we will learn about '''Data Structures''' available in '''Perl'''

| In this tutorial, we will learn about '''Data Structures''' available in '''Perl'''

|-

|-

|Here I am using ''' Ubuntu Linux12.04 ''' operating system and '''Perl 5.14.2'''

|Here I am using ''' Ubuntu Linux12.04 ''' operating system and '''Perl 5.14.2'''

   

   

|-

|-

| I will also be using the '''gedit''' Text Editor.

| I will also be using the '''gedit''' Text Editor.

    

    

|-

|-

|You can use any text editor of your choice.  

|You can use any text editor of your choice.  

   

   

|-

|-

| You should have basic knowledge of '''Variables'''  in  '''Perl'''

| You should have basic knowledge of '''Variables'''  in  '''Perl'''

|-

|-

|Knowledge of ''' comments, loops''' and '''conditional statements''' will be an added advantage.  

|Knowledge of ''' comments, loops''' and '''conditional statements''' will be an added advantage.  

|-

|-

| Please go through the relevant spoken tutorials on the '''spoken tutorial''' website.  

| Please go through the relevant spoken tutorials on the '''spoken tutorial''' website.  

|-

|-

|'''Perl'''  has 3 types of ''' data structure - '''

|'''Perl'''  has 3 types of ''' data structure - '''

   

   

|-

|-

|'''Scalar'''

|'''Scalar'''

   

   

|-

|-

| '''Array'''

| '''Array'''

   

   

|-

|-

|'''Hash''' , also, called as ''' Associative Array '''

|'''Hash''' , also, called as ''' Associative Array '''

|-

|-

|'''Scalar:'''  This type of '''data structure''' holds a value of any '''data type.'''  

|'''Scalar:'''  This type of '''data structure''' holds a value of any '''data type.'''  

   

   

|-

|-

|The '''data type''' can be '''string, number, double''' etc.  

|The '''data type''' can be '''string, number, double''' etc.  

|-

|-

|It can also hold the reference to an '''array''' or reference to a '''hash.'''  

|It can also hold the reference to an '''array''' or reference to a '''hash.'''  

|-

|-

|'''Note:''' Reference in '''Perl''' will be covered in subsequent tutorial.  

|'''Note:''' Reference in '''Perl''' will be covered in subsequent tutorial.  

|-

|-

| '''Scalar''' type of  data structure is as simple as declaring the variable.  

| '''Scalar''' type of  data structure is as simple as declaring the variable.  

|-

|-

|'''$count = 12''' semicolon

|'''$count = 12''' semicolon

|-

|-

|''' $string''' =  in single quote  ''' 'I am scalar of type string' ''' semicolon.  

|''' $string''' =  in single quote  ''' 'I am scalar of type string' ''' semicolon.  

   

   

|-

|-

|We can perform the following operations on ''' scalar '''

|We can perform the following operations on ''' scalar '''

   

   

|-

|-

|Assign a value to it  

|Assign a value to it  

   

   

|-

|-

|Assign one '''scalar''' to another  

|Assign one '''scalar''' to another  

   

   

|-

|-

| '''Arithmetic operations''' on '''number''' type of scalars like add, subtract etc  

| '''Arithmetic operations''' on '''number''' type of scalars like add, subtract etc  

   

   

|-

|-

|string operations on string scalar like '''concatenation, substr''' etc  

|string operations on string scalar like '''concatenation, substr''' etc  

|-

|-

|Now let us look at an example of '''scalar data structure.'''  

|Now let us look at an example of '''scalar data structure.'''  

   

   

|-

|-

| Switch to terminal and type '''gedit scalars dot pl''' space '''&''' and press '''Enter.'''  

| Switch to terminal and type '''gedit scalars dot pl''' space '''&''' and press '''Enter.'''  

|-

|-

| This will open the '''scalars dot pl file in gedit. '''

| This will open the '''scalars dot pl file in gedit. '''

   

   

|-

|-

|Type the following code as displayed on the screen.  

|Type the following code as displayed on the screen.  

   

   

|-

|-

|This is the '''declaration''' and '''assignment''' to the '''scalar'''.

|This is the '''declaration''' and '''assignment''' to the '''scalar'''.

   

   

|-

|-

|These are few '''arithmetic operations''' that can be performed on '''number''' type of scalar  

|These are few '''arithmetic operations''' that can be performed on '''number''' type of scalar  

   

   

|-

|-

|These are '''string operations''' that can be performed on '''string''' type of '''scalar'''.  

|These are '''string operations''' that can be performed on '''string''' type of '''scalar'''.  

   

   

|-

|-

| '''substr''' is the '''PERL function''' which provides part of the '''string''' as output.  

| '''substr''' is the '''PERL function''' which provides part of the '''string''' as output.  

   

   

|-

|-

| Here '''index 0''' specifies start of a '''string''', i.e. from where we want to start extraction of the '''string. '''

| Here '''index 0''' specifies start of a '''string''', i.e. from where we want to start extraction of the '''string. '''

|-

|-

|And 11 specify the '''offset''' upto where we want the '''string''' to be in the output.  

|And 11 specify the '''offset''' upto where we want the '''string''' to be in the output.  

   

   

|-

|-

|Press '''ctrl + s''' to save the file.  

|Press '''ctrl + s''' to save the file.  

   

   

|-

|-

| Then switch to the terminal and execute the '''Perl script''' as  

| Then switch to the terminal and execute the '''Perl script''' as  

|-

|-

|''' perl scalars dot pl''' and press '''Enter'''  

|''' perl scalars dot pl''' and press '''Enter'''  

|-

|-

|  The output shown on terminal is as highlighted

|  The output shown on terminal is as highlighted

|-

|-

|Now, let us look at '''array data structure''' in '''PERL.'''   

|Now, let us look at '''array data structure''' in '''PERL.'''   

   

   

|-

|-

|'''Array:'''  It is a list of  elements.

|'''Array:'''  It is a list of  elements.

   

   

|-

|-

|Elements can be '''string, number''' etc.  

|Elements can be '''string, number''' etc.  

   

   

|-

|-

| It has an '''index,''' which is used for performing various operations on the '''array'''.  

| It has an '''index,''' which is used for performing various operations on the '''array'''.  

   

   

|-

|-

| '''Index''' starts with zero.  

| '''Index''' starts with zero.  

   

   

|-

|-

| Unlike other programming languages, there is no need to declare an array or its length before using it in Perl.  

| Unlike other programming languages, there is no need to declare an array or its length before using it in Perl.  

   

   

|-

|-

|'''Perl array''', stretches or shrinks as per the elements added or removed from it  

|'''Perl array''', stretches or shrinks as per the elements added or removed from it  

   

   

|-

|-

|  The syntax to write an array is;  

|  The syntax to write an array is;  

   

   

|-

|-

|''' at the rate variableName space equal to ''' space open bracket list of elements separated with comma close bracket semicolon  

|''' at the rate variableName space equal to ''' space open bracket list of elements separated with comma close bracket semicolon  

|-

|-

|Now let us look at an example of '''array data structure.'''  

|Now let us look at an example of '''array data structure.'''  

   

   

|-

|-

|Switch to '''terminal''' and type '''gedit perlArray dot pl''' space '''&''' and press '''Enter'''.  

|Switch to '''terminal''' and type '''gedit perlArray dot pl''' space '''&''' and press '''Enter'''.  

   

   

|-

|-

|  This will open the '''perlArray dot pl''' file in '''gedit'''.   

|  This will open the '''perlArray dot pl''' file in '''gedit'''.   

   

   

|-

|-

|Type the following code as displayed on the screen.  

|Type the following code as displayed on the screen.  

   

   

|-

|-

| This is the '''number array''' which has elements of '''number''' type.  

| This is the '''number array''' which has elements of '''number''' type.  

   

   

|-

|-

|  This is the '''string array''' which has elements of '''string''' type.  

|  This is the '''string array''' which has elements of '''string''' type.  

   

   

|-

|-

| This '''array''' has elements of both '''number''' and '''string''' type.  

| This '''array''' has elements of both '''number''' and '''string''' type.  

   

   

|-

|-

| This example shows the various types of '''arrays''' in '''Perl. '''  

| This example shows the various types of '''arrays''' in '''Perl. '''  

|-

|-

| This is how we can print the '''array''' in '''Perl'''.  

| This is how we can print the '''array''' in '''Perl'''.  

|-

|-

|Press '''Ctrl + S''' to save the file.  

|Press '''Ctrl + S''' to save the file.  

    

    

|-

|-

|Then switch to  terminal and execute the '''Perl script''' as  

|Then switch to  terminal and execute the '''Perl script''' as  

|-

|-

|'''perl perlArray dot pl''' and press '''Enter.'''  

|'''perl perlArray dot pl''' and press '''Enter.'''  

   

   

|-

|-

|The following output is displayed on the terminal

|The following output is displayed on the terminal

|-

|-

|Now, let us look at '''Hash data structure''' in '''Perl'''.  

|Now, let us look at '''Hash data structure''' in '''Perl'''.  

   

   

|-

|-

| '''Hash''' is alternatively called as '''Associative array'''

| '''Hash''' is alternatively called as '''Associative array'''

|-

|-

| It is a '''Key Value pair data structure.'''  

| It is a '''Key Value pair data structure.'''  

   

   

|-

|-

|'''Key''' in '''hash''' is unique.  

|'''Key''' in '''hash''' is unique.  

|-

|-

|If the same '''key''' is added again, then the '''value''' of that '''key''' will be overridden by the latest '''value''' assigned to the '''key'''.  

|If the same '''key''' is added again, then the '''value''' of that '''key''' will be overridden by the latest '''value''' assigned to the '''key'''.  

   

   

|-

|-

|'''Value''' can be duplicate.  

|'''Value''' can be duplicate.  

   

   

|-

|-

|It also holds '''value''' of any '''data type. '''

|It also holds '''value''' of any '''data type. '''

   

   

|-

|-

|The syntax of '''hash''' is;  

|The syntax of '''hash''' is;  

|-

|-

|'''percentage variable name space equal to space open bracket '''

|'''percentage variable name space equal to space open bracket '''

|-

|-

|Press '''Enter '''

|Press '''Enter '''

|-

|-

|'''single quote key Name single quote space equal to greater than sign space Value comma'''  

|'''single quote key Name single quote space equal to greater than sign space Value comma'''  

   

   

|-

|-

| Press '''Enter '''

| Press '''Enter '''

   

   

|-

|-

| '''single quote key Name single quote space equal to greater than sign space Value '''

| '''single quote key Name single quote space equal to greater than sign space Value '''

|-

|-

|Press '''Enter'''  

|Press '''Enter'''  

   

   

|-

|-

| close bracket semicolon  

| close bracket semicolon  

|-

|-

| Now let us look at an example of '''hash data structure'''.  

| Now let us look at an example of '''hash data structure'''.  

   

   

|-

|-

|  Switch to terminal and type  

|  Switch to terminal and type  

|-

|-

| '''gedit perlHash dot pl''' space '''&''' and press '''Enter.'''  

| '''gedit perlHash dot pl''' space '''&''' and press '''Enter.'''  

|-

|-

| This will open the '''perlHash dot pl''' file in '''gedit. '''

| This will open the '''perlHash dot pl''' file in '''gedit. '''

|-

|-

|Type the following code as displayed on the screen.  

|Type the following code as displayed on the screen.  

|-

|-

|  This '''hash''' indicates the marks obtained in a subject.  

|  This '''hash''' indicates the marks obtained in a subject.  

   

   

|-

|-

| This example, shows the use of '''hash'''

| This example, shows the use of '''hash'''

|-

|-

|Now let us see how to print the '''hash'''

|Now let us see how to print the '''hash'''

   

   

|-

|-

| For now, just note the way I have printed the '''hash. '''

| For now, just note the way I have printed the '''hash. '''

|-

|-

|Detailed explanation will be given in  subsequent tutorial.  

|Detailed explanation will be given in  subsequent tutorial.  

|-

|-

|Press '''Ctrl + S''' to save the file.  

|Press '''Ctrl + S''' to save the file.  

|-

|-

|Then switch to  terminal and execute the '''Perl script''' as  

|Then switch to  terminal and execute the '''Perl script''' as  

|-

|-

|  '''perl perlHash dot pl''' and press '''Enter.'''  

|  '''perl perlHash dot pl''' and press '''Enter.'''  

|-

|-

| The following output is displayed on the terminal

| The following output is displayed on the terminal

|-

|-

| Let us summarize.  

| Let us summarize.  

   

   

|-

|-

|  In this tutorial, we have learnt -  

|  In this tutorial, we have learnt -  

   

   

|-

|-

| '''scalar'''

| '''scalar'''

   

   

|-

|-

|'''Array''' and  

|'''Array''' and  

   

   

|-

|-

|'''Hash Data Structure''' in '''Perl'''  

|'''Hash Data Structure''' in '''Perl'''  

 

 

|-

|-

|  using sample programs.  

|  using sample programs.  

   

   

|-

|-

| There is assignment for you -  

| There is assignment for you -  

|-

|-

| Declare '''scalar variable'''  

| Declare '''scalar variable'''  

|-

|-

| Assign value of '''type float''' to it and then print it.  

| Assign value of '''type float''' to it and then print it.  

|-

|-

| Declare and print an array of colors 'Red', 'Yellow' and 'Green'.  

| Declare and print an array of colors 'Red', 'Yellow' and 'Green'.  

   

   

|-

|-

|Declare and print a '''hash''' of Employee Name and their department.  

|Declare and print a '''hash''' of Employee Name and their department.  

|-

|-

| Hint: ''' 'Employee' =>(equal to greater than sign)  'John'''' comma  

| Hint: ''' 'Employee' =>(equal to greater than sign)  'John'''' comma  

|-

|-

| ''' 'Department' =>(equal to greater than sign) 'Engineering' '''

| ''' 'Department' =>(equal to greater than sign) 'Engineering' '''

|-

|-

|Watch the video available at the following link

|Watch the video available at the following link

   

   

|-

|-

|It summaries the Spoken Tutorial project

|It summaries the Spoken Tutorial project

    

    

|-

|-

|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

   

   

|-

|-

|  The Spoken Tutorial Project Team  Conducts workshops using spoken tutorials

|  The Spoken Tutorial Project Team  Conducts workshops using spoken tutorials

   

   

|-

|-

|Gives certificates to those who pass an online  test

|Gives certificates to those who pass an online  test

   

   

|-

|-

|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

   

   

|-

|-

|  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

    

    

|-

|-

|It is supported by the National Mission on Education through ICT, MHRD, Government of India.

|It is supported by the National Mission on Education through ICT, MHRD, Government of India.

   

   

|-

|-

|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

   

   

|-

|-

|  Hope you enjoyed this Perl tutorial.  

|  Hope you enjoyed this Perl tutorial.  

   

   

|-

|-

|This is Amol signing off.

|This is Amol signing off.

    

    

|-

|-

|Thanks for joining.

|Thanks for joining.

   

   

|}

|}