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PHP reset first level of array without loop

I have a simple multidimensional array like

$array = array(
    array('key1'=>array('a','b')),
    array('key2'=>array('c','d'), 'key3'=>array('e','f')),
    array('key4'=>array('g','h'), 'key5'=>array('i','j'), 'key6'=>array('k','l', 'm'))
);

and I would reset its first level like next

$array = array(
    'key1'=>array('a','b'),
    'key2'=>array('c','d'),
    'key3'=>array('e','f'),
    'key4'=>array('g','h'),
    'key5'=>array('i','j'),
    'key6'=>array('k','l','m')
);

I know this is pretty easy with a loop foreach

to achieve, but I'm wondering if it can be done with one line code.

What I have tried so far

array_map('key', $array);

but it only returns the first key of the child array.

Any thoughts?

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2 answers


PHP 5.6 introduces variable functions in PHP, which allows you to write functions that take any additional argument into the same array using the splat: operator ...

.

Another - perhaps lesser known - use of this operator is that it works the other way around. By placing this operator in front of an array in a function call, it makes that function accept the entries of that array as if you had written them in a string.

Allows you to enter:



$array = array_merge(... $array);

Sending a $ array will usually return the $ array unchanged. Using splat allows you to array_merge

work with the number of undefined 2nd level arrays in it. Since array_merge is itself a variation function that concatenates whatever arrays you send to it, it works.

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try this: it worked with array_reduce

.

$result = array_reduce($array, function($final, $value) {
    return array_merge($final, $value);
}, array());


online example

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