Is there a function to extract a 'column' from an array in PHP?

Question

I have an array of arrays, with the following structure:

array(array('page' => 'page1', 'name' => 'pagename1')
      array('page' => 'page2', 'name' => 'pagename2')
      array('page' => 'page3', 'name' => 'pagename3'))

Is there a built-in function that will return a new array with just the values of the 'name' keys? so I'd get:

array('pagename1', 'pagename2', 'pagename3')

Answer 1

Do you mean array_values?

Edit: Thanks for the comment-less downvote. If whoever had taken the time to actually look at the documentation for the function, you'd have seen the first comment that gives an example of writing your own array_values_recursive function. Combine that with an array_walk and you'd have a pretty nifty function that wouldn't have the 'name' column hardcoded into it. Sheesh.

Answer 2

Why does it have to be a built in function? :) No, there is none, write your own.

Here is a nice and easy one, as opposed to others in this thread.

$namearray = array();

foreach ($array as $item) {
    $namearray[] = $item['name'];
}

Answer 3

Here's a functional way of doing it:

$data = array(
            array('page' => 'page1', 'name' => 'pagename1'),
            array('page' => 'page2', 'name' => 'pagename2'),
            array('page' => 'page3', 'name' => 'pagename3'));

$result = array_map(create_function('$arr', 'return $arr["name"];'), $data);
print_r($result);

Answer 4

Similar to fuentesjrs solution, but a bit more generic using array_walk() with a custom callback:

// Define the callback
function extract_named_sub_elements(&$item, $key, $name) {
  $item = $item[$name];
}

// Test data
$original = array(
  array('page' => 'page1', 'name' => 'pagename1'),
  array('page' => 'page2', 'name' => 'pagename2'),
  array('page' => 'page3', 'name' => 'pagename3'),
);

// Use a copy, as array_walk() operates directly on the passed in array
$copy = $original;

// Substitute 'name' with whatever element you want to extract, e.g. 'page'
array_walk($copy, 'extract_named_sub_elements', 'name');

print_r($copy);

Answer 5

You can extend the ArrayIterator class and override the method mixed current(void).

class Foo extends ArrayIterator {
  protected $index;
  public function __construct($array, $index) {
    parent::__construct($array);
    $this->index = $index;
  }

  public function current() {
    $c = parent::current();
    return isset($c[$this->index]) ? $c[$this->index] : null;
  }
}

$a = array(
  array('page' => 'page1', 'name' => 'pagename1'),
  array('name' => '---'),
  array('page' => 'page2', 'name' => 'pagename2'),
  array('page' => 'page3', 'name' => 'pagename3')
);

$f = new Foo($a, 'page');
foreach($f as $e) {
  echo $e, "\n";
}

prints

page1

page2
page3

Answer 6

I don't think there is any need to have a built in function for this. There may be an array in your those array.

$samples=array(
            array('page' => 'page1', 'name' => 'pagename1'),
            array('page' => 'page2', 'name' => 'pagename2'),
            array('page' => 'page3', 'name' => 'pagename3')
            );

$output1=array();
$output2=array();
foreach($samples as $sample){
    array_push($output1,$sample['name']);
    $output2[]=array_splice($sample,1);

}

print_r($output1);
print_r($output2);

in $output1 is the output what you want if you want only to remove the 'page' indexing' part then $output2.

if you need all the values from the that array and indexes numerically the array then you can use

$array_1=array_values($samples);

but what i understand, you didn't want this.