DocumentationHSLReferenceFunctionHH\Lib\Dict\from_values

HH\Lib\Dict\from_values

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This is available as Dict\from_values in the www repository.

Returns a new dict keyed by the result of calling the given function on each corresponding value

namespace HH\Lib\Dict;

function from_values<Tk as arraykey, Tv>(
  Traversable<Tv> $values,
  (function(Tv): Tk) $key_func,
): dict<Tk, Tv>;

In the case of duplicate keys, later values will overwrite the previous ones.

To create a dict from keys, see Dict\from_keys().
To create a dict from key/value tuples, see Dict\from_entries().
To create a dict containing all values with the same keys, see Dict\group_by().

Time complexity: O(n) Space complexity: O(n)

Parameters

Traversable<Tv>$values
(function(Tv): Tk) $key_func

Returns

dict<Tk, Tv>

Examples

$original_dict_1 = dict[1 => 1, 2 => 2, 3 => 3];
$from_values_dict_1 = Dict\from_values($original_dict_1, $x ==> $x + 1);
echo "Resulting from values dict 1: \n";
\print_r($from_values_dict_1);
//Output: Resulting from values dict 1:
//dict[2 => 1, 3 => 2, 4 => 3]

$original_dict_2 = dict[1 => 1, 2 => 2, 3 => 3];
$from_values_repeat_value_dict_2 = Dict\from_values($original_dict_2, $x ==> $x * 0);
echo "Resulting from repeat values dict 2: \n";
\print_r($from_values_repeat_value_dict_2);
//Output: Resulting from repeat values dict 2: 
//dict[0 => 3]