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pull

Note

This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information.

Returns a new dict with mapped keys and values

namespace HH\Lib\Dict;

function pull<Tk as arraykey, Tv1, Tv2>(
  Traversable<Tv1> $traversable,
  (function(Tv1): Tv2) $value_func,
  (function(Tv1): Tk) $key_func,
): dict<Tk, Tv2>;
  • values are the result of calling $value_func on the original value
  • keys are the result of calling $key_func on the original value. In the case of duplicate keys, later values will overwrite the previous ones.

Time complexity: O(n * (f1 + f2), where f1 is the complexity of $value_func and f2 is the complexity of $key_func Space complexity: O(n)

Parameters​

  • Traversable<Tv1>$traversable
  • (function(Tv1): Tv2) $value_func
  • (function(Tv1): Tk) $key_func

Returns​

  • dict<Tk, Tv2>