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PHP Array Exercises : Function to sort subnets

PHP Array: Exercise-21 with Solution

Write a PHP function to sort subnets.

Sample Solution:

PHP Code:

<?php
function sort_subnets ($x, $y) {
    $x_arr = explode('.', $x);
    $y_arr = explode('.', $y);
    foreach (range(0,3) as $i) {
        if ( $x_arr[$i] < $y_arr[$i] ) {
            return -1;
        }
        elseif ( $x_arr[$i] > $y_arr[$i] ) {
            return 1;
        }
    }
    return -1;
}

$subnet_list = 
array('192.169.12',
'192.167.11',
'192.169.14',
'192.168.13',
'192.167.12',
'122.169.15',
'192.167.16'
);
usort($subnet_list, 'sort_subnets');
print_r($subnet_list);
?>

Sample Output: 

Array                                                       
(                                                           
    [0] => 122.169.15                                       
    [1] => 192.167.11                                       
    [2] => 192.167.12                                       
    [3] => 192.167.16                                       
    [4] => 192.168.13                                       
    [5] => 192.169.12                                       
    [6] => 192.169.14                                       
)

Flowchart:

Flowchart: PHP - Sort subnets

PHP Code Editor:

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Previous: Write a PHP function to sort an array according to another array acting as a priority list.
Next: Write a PHP script to sort the following array by the day (page_id) and username.

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PHP: Tips of the Day

Convert a PHP object to an associative array

Just typecast it

$array = (array) $yourObject;

From Arrays:

If an object is converted to an array, the result is an array whose elements are the object's properties. The keys are the member variable names, with a few notable exceptions: integer properties are unaccessible; private variables have the class name prepended to the variable name; protected variables have a '*' prepended to the variable name.These prepended values have null bytes on either side.

Example: Simple Object

$object = new StdClass;
$object->foo = 1;
$object->bar = 2;

var_dump( (array) $object );

Output:

array(2) {
  'foo' => int(1)
  'bar' => int(2)
}

Example: Complex Object

class Foo
{
    private $foo;
    protected $bar;
    public $baz;

    public function __construct()
    {
        $this->foo = 1;
        $this->bar = 2;
        $this->baz = new StdClass;
    }
}

var_dump( (array) new Foo );

Output (with \0s edited in for clarity):

array(3) {
  '\0Foo\0foo' => int(1)
  '\0*\0bar' => int(2)
  'baz' => class stdClass#2 (0) {}
}

Output with var_export instead of var_dump:

array (
  '' . "\0" . 'Foo' . "\0" . 'foo' => 1,
  '' . "\0" . '*' . "\0" . 'bar' => 2,
  'baz' =>
  stdClass::__set_state(array(
  )),
)

Typecasting this way will not do deep casting of the object graph and you need to apply the null bytes (as explained in the manual quote) to access any non-public attributes. So this works best when casting StdClass objects or objects with only public properties. For quick and dirty (what you asked for) it's fine.

Also see this in-depth blog post:

  • Fast PHP Object to Array conversion

Ref : https://bit.ly/3fqiV2E