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Arrays (push, pop, shift, unshift) in Perl

Arrays are fundamental structures in Perl, allowing you to store ordered lists of scalar values. Four key functions �� push, pop, shift, and unshift �� are frequently used for adding or removing elements from either the beginning or the end of arrays.

Let's delve into a tutorial on these functions and their usage with arrays in Perl.

1. push Function:

The push function appends one or more values to the end of an array.

Usage:

my @fruits = ("apple", "banana");
push @fruits, "cherry", "date";
# @fruits now contains: ("apple", "banana", "cherry", "date")

2. pop Function:

The pop function removes and returns the last value of an array. If the array is empty, undef is returned.

Usage:

my @fruits = ("apple", "banana", "cherry");
my $last_fruit = pop @fruits;
# $last_fruit now holds "cherry"
# @fruits now contains: ("apple", "banana")

3. shift Function:

The shift function removes and returns the first value of an array. Like pop, if the array is empty, undef is returned.

Usage:

my @fruits = ("apple", "banana", "cherry");
my $first_fruit = shift @fruits;
# $first_fruit now holds "apple"
# @fruits now contains: ("banana", "cherry")

4. unshift Function:

The unshift function prepends one or more values to the beginning of an array.

Usage:

my @fruits = ("banana", "cherry");
unshift @fruits, "apple";
# @fruits now contains: ("apple", "banana", "cherry")

5. Best Practices:

Avoid Shifting Large Arrays Often: Both shift and unshift require all the other elements of the array to be moved up or down a position, respectively. This can be inefficient with large arrays.
Using push/pop for Stack Operations: If you're implementing a stack (last-in, first-out data structure), you can use an array with the push and pop functions. This gives you an efficient way of implementing this data structure.
Return Value Handling: Remember that pop and shift will return undef if the array is empty. This can be a potential source of bugs if not handled correctly.

Summary:

push: Add elements to the end of an array.
pop: Remove and return the last element of an array.
shift: Remove and return the first element of an array.
unshift: Add elements to the beginning of an array.

Using these functions effectively can help in managing and manipulating your data in Perl arrays. They provide the fundamental operations that, combined with other Perl array functions, offer a high level of flexibility when working with lists.

Using push() and pop() with Perl arrays:

Description: Use push() to append elements and pop() to remove the last element.

Code:

my @stack = (1, 2, 3);

# Appending elements with push
push @stack, 4;

# Removing the last element with pop
my $last_element = pop @stack;

Appending and removing elements in Perl arrays:

Description: Demonstrate the basic use of push() and pop() for array manipulation.

Code:

my @numbers = (10, 20, 30);

# Appending elements with push
push @numbers, 40;

# Removing the last element with pop
my $removed_element = pop @numbers;

Shift and unshift operations in Perl arrays:

Description: Use shift() to remove the first element and unshift() to insert elements at the beginning.

Code:

my @queue = (1, 2, 3);

# Removing the first element with shift
my $first_element = shift @queue;

# Inserting elements at the beginning with unshift
unshift @queue, 4, 5;

Manipulating arrays with push and pop in Perl:

Description: Combine push() and pop() for dynamic array manipulation.

Code:

my @dynamic_array = (10, 20, 30);

# Appending elements with push
push @dynamic_array, 40, 50;

# Removing the last element with pop
my $removed_item = pop @dynamic_array;

Adding and deleting elements using Perl array push and pop:

Description: Use push() for adding and pop() for deleting elements in an array.

Code:

my @playlist = ('Song1', 'Song2', 'Song3');

# Adding a new song with push
push @playlist, 'Song4';

# Deleting the last song with pop
my $last_song = pop @playlist;

Inserting elements at the beginning with unshift in Perl:
- Description: Use unshift() to insert elements at the beginning of an array.
- Code:
```
my @queue = (2, 3, 4);

# Inserting elements at the beginning with unshift
unshift @queue, 1;
```
Removing elements from the front with shift in Perl:
- Description: Use shift() to remove elements from the front of an array.
- Code:
```
my @queue = (1, 2, 3, 4);

# Removing the first element with shift
my $removed_item = shift @queue;
```
Perl array push multiple elements example:
- Description: Use push() to add multiple elements to an array.
- Code:
```
my @array = (1, 2, 3);

# Adding multiple elements with push
push @array, 4, 5, 6;
```

Common array operations with push, pop, shift, and unshift in Perl:

Description: Demonstrate common array operations using push, pop, shift, and unshift.

Code:

my @numbers = (10, 20, 30);

# Appending elements with push
push @numbers, 40;

# Removing the last element with pop
my $removed_item = pop @numbers;

# Inserting elements at the beginning with unshift
unshift @numbers, 5, 15;

# Removing the first element with shift
my $first_item = shift @numbers;