Difference between revisions of "PERL/C2/Array-functions/English"

1. push
2. pop
3. shift
4. unshift
5. split
6. splice
7. join
8. sort
9. qw

I will also be using the gedit Text Editor.

You can use any text editor of your choice.

Knowledge of Comments, loops and conditional statements will be an added advantage.

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

These functions can perform various operations on an Array.

This can be done by using;

1. push function which adds an element at the last position of an Array
2. pop function which removes an element from the last position of an Array

Open the terminal and type gedit perlArray dot pl space ampersand

Press Enter

#!/usr/bin/perl

@myArray = (1, 2, 3);

print "Original array: @myArray\n";

# Insert an element at the last position of an array

push (@myArray, 4);

print "New array after pushing 4 into an array: @myArray\n";

# Remove an element from the last position of an array

pop (@myArray);

print "New array after popping element: @myArray\n";

Type the code as shown on the screen

<<pause>>

Here, we have defined an Array of length 3.

push function will insert an element at the last position of this Array i.e after 3;

wheras, pop function will remove an element from the last position of the Array.

In our case, 4 will be removed from the Array.

1. 1st argument to the push function, is the Array in which to add an element.
2. 2nd argument is the element which is to be pushed into the Array.

• pop function takes only one argument
• It is the Array from which an element needs to be removed.

Both these functions work at last position of an Array.

The syntax for this is -

$variable = pop(@myArray)

perl perlArray.pl

Type perl perlArray dot pl and press Enter.

Original array: 1 2 3

New array after pushing 4 into an array: 1 2 3 4

New array after popping element: 1 2 3

Original array

New array after pushing 4 into an array

New array after popping element

This can be achieved using-

1. unshift function - which adds an element to an Array at the 1st position
2. shift function - which removes the
   first element from an Array.

I will open perlArray dot pl file which I have already created.

# Insert an element at the first position of an array

unshift (@myArray, 0);

print "Array after adding 0 into an array at 1st position: @myArray\n";

# Remove an element from the first position of an array

shift (@myArray);

print "Array after removing element from 1st position: @myArray\n";

unshift function will insert an element at the first position

i.e before 1

shift function will remove an element from the first position.

In our case, zero will be removed.

1. 1st argument is the Array in which to add an element
2. 2nd argument is the element to be added into the Array

• This is the Array from which the element needs to be removed.

Both these functions works at first position of an array.

This syntax for this is -

$variable = shift(@myArray)

perl perlArray.pl

Type perl perlArray dot pl and press Enter.

Array after adding 0 into an array at 1st position: 0 1 2 3

Array after removing element from 1st position: 1 2 3

• The return value of this function is an Array of removed elements.

Go to the perlArray dot pl file which we created earlier.

@myNewArray = (1, 2, 3, 4, 5, 6, 7, 8, 9);

@splicedArray = splice(@myNewArray, 4, 2);

print "Spliced Array: @splicedArray\n";

We need to provide

• the index from where we want to remove the elements and
• the offset upto which we want to remove the elements

In our case, the elements 5 and 6 will be removed.

perl perlArray.pl

perl perlArray dot pl and press Enter.

Spliced Array: 5 6

• The return value of this function is an Array.
• The elements of this Array are the divided portions of the string.

• It returns a string of joined elements.

gedit arrayFunctions.pl &

gedit arrayFunctions dot pl space ampersand

This will open arrayFunctions dot pl file in gedit.

#!/usr/bin/perl

use Data::Dumper;

$string = "Illustration Of Array Functions";

@newArray = split (/ /, $string);

print "Declared String: $string\n\n";

print "Array after split: \n";

print Dumper \@newArray;

print "\n";

$joinedString = join(", ", @newArray);

print "String After Join: $joinedString\n\n";

@sortedArray = sort(@newArray);

print "Array after sorting: @sortedArray\n\n";

@qwArray = qw (Hello Perl Array);

print "Array after qw: \n";

print Dumper \@qwArray;

<<pause>>

In this case, each word of the variable string will become an element of an Array.

Here, each element of newArray will be joined by comma.

sort function will sort the elements of newArray in alphabetical order.

qw function creates an Array of words separated by space.

• 1st is the delimiter by which the string needs to be split
• 2nd is the string which needs to be split.

Delimiters can be specified in forward slash, single or double quotes.

1. 1st is the delimiter by which the Array elements needs to be joined.
2. 2nd is the Array.

Delimiters can be specified in single or double

quotes.

It is not necessary to specify the word in quotes, if written using qw.

perl arrayFunctions.pl

perl arrayFunctions dot pl

and press Enter.

Declared String: Illustration Of Array Functions

Array after split:

$VAR1 = [

'Illustration',

'Of',

'Array',

'Functions'

];

String After Join: Illustration, Of, Array, Functions

Array after sorting: Array Functions Illustration Of

Array after qw:

$VAR1 = [

'Hello',

'Perl',

'Array'

];

<< Will just highlight the output and will not read it while recording >>

In this tutorial, we have learnt to -

• add/remove elements from an Array
• basic functions which can be performed on Array
• using sample programs

1. 'script.spoken-tutorial.org/index.php/Perl' split the above string at '/' delimiter
2. Add https:// at the start of an newly created Array
3. Remove element “Perl” from an Array
4. Declare number Array and sort it

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