PHP - Ds Vector::unshift() Function

The PHP Ds\Vector::unshift() function is used to add values to the front of a vector, moving all existing values forward to make space for the new values.

This function allows you to add multiple values at a time to the front of a vector. It does not return anything but modifies the original vector.

The Ds\Vector class provides another function named insert() allows you to add value at the specified index if the index is 0, an element always will be added to the front of a vector.

Syntax

Following is the syntax of the PHP Ds\Vector::unshift() function −

public Ds\Vector::unshift(mixed $values = ?): void

Parameters

Following is the parameter of this function −

• values − A single or multiple values need to be added.

Return value

This function does not return any value.

Example 1

The following program demonstrates the usage of the PHP Ds\Vector::unshift() function −

<?php 
   $vector = new \Ds\Vector([1, 2, 3, 4]); 
   echo "The original vector: \n"; 
   print_r($vector);
   $value = 5;
   echo "The given value: ".$value;
   echo "\nThe vector elements after inserting new element: \n";
   #using unshift() function
   $vector->unshift($value); 
   print_r($vector);
?>

Output

The above program produces the following output −

The original vector:
Ds\Vector Object
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
)
The given value: 5
The vector elements after inserting new element:
Ds\Vector Object
(
    [0] => 5
    [1] => 1
    [2] => 2
    [3] => 3
    [4] => 4
)

Example 2

We are adding multiple values at the front of a vector at once.

Following is another example PHP Ds\Vector::unshift() function. We use this function to add the specified values at the front of this vector

<?php 
   $vector = new \Ds\Vector(["Tutorials", "Point"]);
   echo "The original vector: \n"; 
   print_r($vector); 
   $val1 = "India";
   $val2 = "Tutorix";
   echo "The given values are: ".$val1.", ".$val2;
   echo "\nThe vector elements after inserting new elements: \n";
   $vector->unshift($val1, $val2);
   print_r($vector); 
?>

Output

After executing the above program, the following output will be displayed −

The original vector:
Ds\Vector Object
(
    [0] => Tutorials
    [1] => Point
)
The given values are: India, Tutorix
The vector elements after inserting new elements:
Ds\Vector Object
(
    [0] => India
    [1] => Tutorix
    [2] => Tutorials
    [3] => Point
)