HH\Lib\Dict\map_keys
Returns a new dict where each key is the result of calling the given function on the original key
namespace HH\Lib\Dict;
function map_keys<Tk1, Tk2 as arraykey, Tv>(
KeyedTraversable<Tk1, Tv> $traversable,
(function(Tk1): Tk2) $key_func,
): dict<Tk2, Tv>;
In the case of duplicate keys, later values will overwrite the previous ones.
Time complexity: O(n * f), where f is the complexity of $key_func
Space complexity: O(n)
Parameters
KeyedTraversable<Tk1,
Tv> $traversable
(function(Tk1): Tk2) $key_func
Returns
dict<Tk2, Tv>