PHP - Ds Map::copy() Function

The PHPDs\Map::copy()function is used to create a shallow copy of a Ds\Map object, and the function returns the same the shallow copy in the result.

A shallow copy of a collection (or map) is a copy where the properties share the same references as those of the source object from which the copy was made.

Syntax

Following is the syntax of the PHP Ds\Map::copy() function −

public Ds\Map::copy(): Ds\Map

Parameters

This function does not accept any parameter.

Return value

This function returns a shallow copy of a map.

Example 1

The following is the basic example of the PHP Ds\Map::copy() function −

<?php  
   $map = new \Ds\Map([1, 2, 3]);
   echo "The map elements are: \n";
   print_r($map);
   echo "\nThe shallow copy of a map: \n";
   #using the copy() function
   print_r($map->copy());
?>

Output

The above program produces the following output −

The map elements are:
Ds\Map Object
(
    [0] => Ds\Pair Object
        (
            [key] => 0
            [value] => 1
        )

    [1] => Ds\Pair Object
        (
            [key] => 1
            [value] => 2
        )

    [2] => Ds\Pair Object
        (
            [key] => 2
            [value] => 3
        )

)

The shallow copy of a map:
Ds\Map Object
(
    [0] => Ds\Pair Object
        (
            [key] => 0
            [value] => 1
        )

    [1] => Ds\Pair Object
        (
            [key] => 1
            [value] => 2
        )

    [2] => Ds\Pair Object
        (
            [key] => 2
            [value] => 3
        )

)

Example 2

Following is another example of the PHP Ds\Map::copy() function. We use this function to retrieve a shallow copy of this map (["Tutorials", "Point", "India"]) −

<?php 
   $map = new \Ds\Map(["Tutorials", "Point", "India"]);
   echo "The map elements are: \n";
   print_r($map);
   print_r("The shallow copy of a map: \n");
   #using copy() function
   print_r($map->copy()); 
?>

Output

After executing the above program, it will display the following output −

The map elements are:
Ds\Map Object
(
    [0] => Ds\Pair Object
        (
            [key] => 0
            [value] => Tutorials
        )

    [1] => Ds\Pair Object
        (
            [key] => 1
            [value] => Point
        )

    [2] => Ds\Pair Object
        (
            [key] => 2
            [value] => India
        )

)
The shallow copy of a map:
Ds\Map Object
(
    [0] => Ds\Pair Object
        (
            [key] => 0
            [value] => Tutorials
        )

    [1] => Ds\Pair Object
        (
            [key] => 1
            [value] => Point
        )

    [2] => Ds\Pair Object
        (
            [key] => 2
            [value] => India
        )

)

Example 3

In the example below, we use the copy() function to create a shallow copy of this map (['a', 'b']) −

<?php 
   $map = new \Ds\Map(['a', 'b']);
   echo "The map elements are: \n";
   foreach($map as $key=>$value){
	   echo "[".$key."] = ".$value."\n";
   }
   print_r("The shallow copy of a map: \n");
   #using copy() function
   $shallow_cpy = $map->copy();
   foreach($shallow_cpy as $key=>$value){
	   echo "[".$key."] = ".$value."\n";
   }
?>

Output

Once the above program is executed, it will display the following output −

The map elements are:
[0] = a
[1] = b
The shallow copy of a map:
[0] = a
[1] = b