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Created page with ''''Title Of Script: Hash in Perl''' '''Author:''' Amol Brahmankar '''Keywords: '''Hash in perl, Associative Array in Perl video tutorial. {| style="border-spacing:0;" | styl…'

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'''Title Of Script: Hash in Perl'''

'''Author:''' Amol Brahmankar

'''Keywords: '''Hash in perl, Associative Array in Perl video tutorial.

{| style="border-spacing:0;"
| style="border-top:0.0007in solid #000000;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| <center>'''Visual Cue'''</center>
| style="border:0.0007in solid #000000;padding:0.0382in;"| <center>'''Narration'''</center>

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Welcome to the spoken tutorial on '''Hash''' in '''Perl.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide: Learning Objectives
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| In this tutorial, we will learn about;

* '''Hash''' in '''Perl '''and
* Accessing element of a '''hash'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide: System Requirements
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| For this tutorial, I am using

* '''Ubuntu Linux12.04''' operating system
* '''Perl 5.14.2 '''and
* '''gedit '''Text Editor

You can use any text editor of your choice.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide: Prerequisites
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| To practise this tutorial, you should have knowledge of '''Variables & Data Structures '''in''' Perl.'''

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

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

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| * '''Hash''' is an unordered collection of data
* It's a '''key/value pair data structure'''
* '''Hash keys''' are unique
* However, '''Hash''' can have duplicate values

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| The syntax of '''hash '''is as shown.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Let us see how to get the value of a '''key '''from '''hash'''.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide

$hashName{'KeyName'}
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| The syntax for accessing the value of a '''key '''is

'''dollar hashName open curly bracket single quote keyName single quote close curly bracket'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Let us understand '''hash''' using a sample program.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Switch to gedit with '''perlHash.pl '''opened
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| I have already typed the code in '''perlHash dot pl''' file in '''gedit'''.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| '''Gedit'''

'''<nowiki>#!/usr/bin/perl </nowiki>'''

'''%hash = ( '''

''''Name' => 'John', '''

''''Department' => 'Finance' '''

'''); '''

'''print "Value of Key Name is: ", $hash{'Name'}, "\n";'''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Type the code as shown in your '''perlHash dot pl '''file.

<nowiki><<pause>></nowiki>

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| '''%hash'''

'''highlight keys 'Name' & 'Department''''

'''highlight values 'John' & 'Finance''''

'''$hash{'Name'}'''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| '''Hash''' in '''Perl''' is declared with '''percentage''' sign.

These are the '''keys''' of '''hash.'''

And these are the '''values''' of '''hash.'''

'''Note:''' To access '''key''' of '''hash''', one has to use '''dollar '''sign.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| '''Slide'''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Press '''Ctrl + S '''to save the file.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Switch to terminal

'''perl perlHash.pl'''

| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Then switch to the '''terminal '''and '''execute '''the '''Perl script '''as''' '''

'''perl perlHash dot pl'''

and press''' Enter.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Highlight the output on the terminal

Value of Key Name is: John
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| The output is as shown on '''terminal'''<nowiki>. <pause></nowiki>

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Now let us see add and delete of '''keys''' from a '''hash'''.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| The syntax for

1. adding key is

'''dollar hashName open curly bracket'''

'''single quote KeyName single quote close '''

'''curly bracket equal to value semicolon'''

2. deleting key is

'''delete dollar hashName open curly bracket'''

'''single quote KeyName single quote close '''

'''curly bracket semicolon'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Now, let us understand this using a sample program.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Terminal hashKeyOperations dot pl
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| I have already typed the code in '''hashKeyOperations dot pl''' file in '''gedit'''.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Type the code as shown in your '''hashKeyOperations dot pl '''file.

<nowiki><<pause>></nowiki>

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| <nowiki>#!/usr/bin/perl </nowiki>

use Data::Dumper;

<nowiki>#Hash of marks obtained in a subject </nowiki>

%hash = (

'Subject' => 'Math',

'Marks' => 98

);

print "Hash before adding keys\n";

print Dumper \%hash;

<nowiki>#Add Name and roll number of a student </nowiki>

$hash{'Name'} = 'Amol';

$hash{'RollNumber'} = 12;

print "Hash after addition of Name & RollNumber keys\n";

print Dumper \%hash;

delete $hash{'RollNumber'};

print "Hash after deletion of RollNumber key\n";

print Dumper \%hash;
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| This is the declaration of '''hash.'''

We'll be adding, deleting the '''keys '''from this '''hash.'''

Here we are adding a '''key '''to an already created '''hash.'''

It is like assigning a '''value '''to a '''variable.'''

'''delete''' keyword is used to delete the '''key'''.

We need to pass the '''key''' to delete it.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Press '''Ctrl+S''' to save the file.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Terminal

'''perl hashKeyOperations.pl '''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Switch to the '''terminal '''and execute the '''Perl script '''as

'''perl hashKeyOperations dot pl '''and press '''Enter.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Hash before adding keys

$VAR1 = {

'Subject' => 'Math',

'Marks' => 98

};

Hash after addition of Name & RollNumber keys

$VAR1 = {

'Subject' => 'Math',

'RollNumber' => 12,

'Marks' => 98,

'Name' => 'Amol'

};

Hash after deletion of RollNumber key

$VAR1 = {

'Subject' => 'Math',

'Marks' => 98,

'Name' => 'Amol'

};
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Output will be as shown on the '''terminal.'''

<nowiki><<pause>></nowiki>

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Let us look at '''sorting''' of a '''hash keys '''and''' values.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Syntax to '''sort keys''' is

'''sort open bracket keys percentage hashName close bracket semicolon'''

Similarly, we can '''sort hash values '''as

'''sort open bracket values percentage hashName close bracket semicolon'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Let us understand '''sorting '''functionality using a sample program.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Let me switch to '''sortHash dot pl '''on '''gedit.'''

Type the code as displayed on the screen in''' '''your '''sortHash dot pl '''file.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| <nowiki>#!//usr/bin/perl </nowiki>

%addressHash = (

'City' <nowiki>=> 'Pune', </nowiki>

'State' <nowiki>=> 'Maharashtra', </nowiki>

'Country' => 'India'

);

foreach $key (sort(keys %addressHash)) {

print "Key: ", $key, " ==> ", $addressHash{$key}, "\n";

}

foreach $value (sort(values %addressHash)) {

print "Value: $value\n";

}
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Here we have declared '''hash''' of '''address'''.

Here, to sort the '''keys''' we have used the '''sort''' inbuilt function, along with the '''keys '''function.

This will sort the '''hash keys '''in alphabetical order.

Similarly, we can use the '''sort '''function on '''values '''of '''hash'''.

Sorting can also be done on '''numeric keys''' and/or '''values'''.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Save the file and switch to '''terminal.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Terminal

'''perl sortHash.pl'''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Execute the script by typing

'''perl sortHash dot pl'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Key: City ==> Pune

Key: Country ==> India

Key: State ==> Maharashtra

Value: India

Value: Maharashtra

Value: Pune
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| The output will be as shown on the '''terminal.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Now, let us '''see '''how to get all '''keys''' and '''values''' of '''hash.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| '''Perl''' provides inbuilt function to fetch all the '''hash''' '''keys''' and '''values'''.

# '''keys''' function is used to retrive all the '''keys''' of '''hash'''
# '''values''' function returns '''values '''of all the keys whereas
# '''each''' function iterates over '''hash '''and returns '''key/value '''pair from '''hash'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Gedit
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Let us understand these functions using a sample program.

For this, we'll use '''perlHash dot pl''' script, which we created earlier in this tutorial.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Gedit

'''<nowiki>#!/usr/bin/perl </nowiki>'''

'''%hash = ( '''

''''Name' => 'John', '''

''''Department' => 'Finance' '''

'''); '''

'''print "Value of Key Name is: ", $hash{'Name'}, "\n"; '''

'''@keysOfHash = keys(%hash); '''

'''print "Keys of a Hash are: @keysOfHash\n"; '''

'''@valuesOfHash = values(%hash); '''

'''print "Values of a Hash are: @valuesOfHash\n"; '''

'''while (($key, $value) = each(%hash)) { '''

'''print "key: $key and value: $value\n"; '''

'''}'''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Type the following piece of code as shown on the screen;

<nowiki><<pause>></nowiki>

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Highlight comma in print statement

'''@keysOfHash = keys(%hash); '''

'''@valuesOfHash = values(%hash); '''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Let us understand the code now.

'''keys''' function on '''hash,''' returns an '''array''' which contains all '''keys''' of '''hash.'''

'''values''' function on '''hash''' returns an''' array''' of '''values''' for all '''keys''' of '''hash.'''

'''each '''function''' '''returns the '''key/value''' pair.

Here, we have used the '''while loop.'''

It will iterate over each '''key/value''' pair of '''hash, '''that is returned by '''each function.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Press '''Ctrl+S''' to save the file.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Terminal

'''perl perlHash.pl'''

| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Now, let us execute the script on the '''terminal''' by typing

'''perl perlHash dot pl'''

Press '''Enter'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| '''Value of Key Name is: John '''

'''Keys of a Hash are: Department Name '''

'''Values of a Hash are: Finance John '''

'''key: Department and value: Finance '''

'''key: Name and value: John '''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| The following output will be seen on the '''terminal.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Now let us see few other ways of looping over '''Hash.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide

foreach $variable (keys(%hashName)) {

<nowiki># Action to be performed</nowiki>

}
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| We can use '''foreach loop '''to iterate over each key of '''Hash'''.

Then perform a set of actions on the value of a '''key.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| On the Slide, point to each of the words as per the narration.

| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| The syntax is as displayed on the screen.

Here, each iteration of '''foreach loop '''will assign''' key '''from '''hash '''to '''$variable.'''

Then it will use that '''$variable''' to fetch the '''value '''or to perform a set of actions.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| foreach $variable (values(%hashName)) {

<nowiki># Action to be performed</nowiki>

'''}'''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Similarly, we can loop over '''hash values '''as shown on the screen.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Gedit
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| We will look at a sample program. So, let me switch to '''loopingOverHash dot pl''' in '''gedit.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| '''<nowiki>#!/usr/bin/perl </nowiki>'''

'''%hash = ( '''

''''Name' => 'John', '''

''''Department' => 'Finance' '''

'''); '''

'''foreach $key (keys(%hash)) { '''

'''print "Key is $key and it's value is $hash{$key}\n"; '''

'''} '''

'''print "======================================\n"; '''

'''foreach $value (values(%hash)) { '''

'''print "Value is $value\n"; '''

'''} '''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Type the following piece of code as shown in your '''loopingOverHash dot pl '''file.

<nowiki><<pause>></nowiki>

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Highlight

'''foreach $key (keys(%hash))'''

| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| This piece of code returns single '''key '''of '''hash.'''

Here in our case,

1st time '''dollar key ($key) '''contains the '''Department '''as '''key.'''

In the next iteration of '''foreach, Name key '''is''' '''returned.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Switch back to the slides
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Note: '''Hash '''is an unordered collection of data.

So, '''keys '''returned will not be in the sequence defined at the time of creating '''hash.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| '''Back to gedit'''

'''foreach $value (values(%hash))'''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| The loop on '''values '''works in a similar way.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Press ctrl + s
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Press '''Ctrl + S '''to save the file.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Switch to terminal

'''perl loopingOverHash.pl'''

| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Then, switch to the '''terminal '''and execute the '''Perl script '''as''' '''

'''perl loopingOverHash dot pl'''

and press''' Enter.'''

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Highlight the output on the terminal

'''Key is Department and it's value is Finance '''

'''Key is Name and it's value is John '''

'''<nowiki>====================================== </nowiki>'''

'''Value is Finance '''

'''Value is John '''
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| The following output is displayed on the '''terminal.'''

<nowiki><pause></nowiki>

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide: Summary
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Let us summarize.

In this tutorial, we learnt -

* '''Hash '''in '''Perl '''and
* Accessing '''elements '''of a '''hash'''
* using sample programs.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Slide: Assignment
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Here is assignment for you -

# Declare '''hash''' having student name as '''key'''
# And his/her percentage as the '''value'''.
# Loop over '''hash''' using '''keys, values '''and '''each '''function
# Then print the '''percentage''' of each student.

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| About the Project
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| 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

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Spoken Tutorial Workshops
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| 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

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"| Acknowledgment

http://spoken-tutorial.org\NMEICT-Intro
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| 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.

More information on this Mission is available

spoken hypen tutorial dot org slash NMEICT hyphen Intro

|-
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:none;padding:0.0382in;"|
| style="border-top:none;border-bottom:0.0007in solid #000000;border-left:0.0007in solid #000000;border-right:0.0007in solid #000000;padding:0.0382in;"| Hope you enjoyed this '''Perl''' tutorial.

This is Amol Brahmankar signing off.

Thanks for joining

|}

PERL/C2/Hash-in-Perl/English - Revision history

Nancyvarkey: moved PERL/C2/More-on-Hash/English to PERL/C2/Hash-in-Perl/English

Nancyvarkey at 07:17, 7 March 2014

AmolBrahmankar: Created page with ''''Title Of Script: Hash in Perl''' '''Author:''' Amol Brahmankar '''Keywords: '''Hash in perl, Associative Array in Perl video tutorial. {| style="border-spacing:0;" | styl…'

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