Remove all sub arrays for multidimensional array in PHP

What is a simple mode, in PHP, to remove all the sub arrays of a multidimensional array? What I want is to remove all the开发者_如何学Go sub arrays but the top one...

Thanks, titel

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foreach($array as $k => $a) {
    if (is_array($a)) { unset($array[$k]); }
}

Like this?

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function FlattenCallback($Value) { return !is_array($Value); }

$OneDimension = array_filter($MultiDimension, 'FlattenCallback');