从键和某些子数组值创建数组的简单方法？

Question

I have a source array that looks like this:

$data = array(
    'foo' => array(
        'bar' => 'foo_bar',
        'baz' => 'foo_baz'
    ),
    'fizz' => array(
        'bar' => 'fizz_bar',
        'baz' => 'fizz_baz'
    )
);

I would like to create another array by selecting a key: bar or baz, which will return all of the root keys with the values of the specified key?

some_function($data, 'bar') == array(
    'foo' => 'foo_bar',
    'fizz' => 'fizz_bar'
);

Is there a built-in php function(s) to generate the following results without doing my own loops?

Answer 1

$data = array(
    'foo' => array(
        'bar' => 'foo_bar',
        'baz' => 'foo_baz'
    ),
    'fizz' => array(
        'bar' => 'fizz_bar',
        'baz' => 'fizz_baz'
    )
);

To select bar:

$result = array_combine(
    array_keys($data),
    array_column($data, 'bar')
);

Here's an example:

php > var_dump(array_combine(array_keys($data), array_column($data, 'bar')));
array(2) {
  ["foo"]=>
  string(7) "foo_bar"
  ["fizz"]=>
  string(8) "fizz_bar"
}

Note that array_column() was introduced in PHP 5.5.