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

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

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

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

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

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

|'''Scalar'''

| '''Array'''

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

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

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

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

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

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

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

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

|Assign a value to it  

|Assign one '''scalar''' to another  

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

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

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

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

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

|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'''.  

| 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.  

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

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

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

|  The output shown on terminal is as highlighted

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

| 03:16

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

|   03:22

| 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  

|  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  

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

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

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

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

|The following output is displayed on the terminal

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

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

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

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

|The syntax of '''hash''' is;

|Press '''Enter '''

 

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

| close bracket semicolon  

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

|  Switch to terminal and type  

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

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

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

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

| The following output is displayed on the terminal

| Let us summarize.  

|  In this tutorial, we have learnt -  

| '''scalar'''

   

|'''Array''' and  

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

| using sample programs.  

| There is assignment for you -  

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

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

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

|Watch the video available at the following link

|It summaries the Spoken Tutorial project

|If you do not have good bandwidth, you can download and watch it

| The Spoken Tutorial Project Team Conducts workshops using spoken tutorials

|Gives certificates to those who pass an online  test

|For more details, please write to contact at spoken hyphen tutorial dot org

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| Hope you enjoyed this Perl tutorial.  

|This is Amol signing off.