ContainsKey - Hhvm — ContextQMD

:::info[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. :::

Determines if the specified key is in the current collection

Hack

public function containsKey(
  mixed $k,
): bool;

Guide

Constraints

Parameters

mixed $k

Returns

bool - true if the specified key is present in the current collection; false otherwise.