Checks if a key exists.

@param  string|array  $key
@return bool
5909
public function exists($key)
    {
        $placeholder = new stdClass;

        return ! collect(is_array($key) ? $key : func_get_args())->contains(function ($key) use ($placeholder) {
            return $this->get($key, $placeholder) === $placeholder;
        });
    }
720766
public function has($key)
    {
        // For performance, we can use isset,
        // but it will not match if value == 0
        return isset($this->values[$key]) || array_key_exists($key, $this->values);
    }
433328
public function has(string $key): bool
    {
        $key = $this->prepareKey($key);
        return Arr::has($this->properties, $key);
    }
1207867
public function has(string $key): bool
    {
        $this->assertRead();

        return \array_key_exists($key, $this->data);
    }
113950
public function exists($key) {
        $key = $this->secureKey($key);
        
        if (isset($_SESSION[$key])) return true;
        
        return false;
    }
474754
public function exists($key) {

		$files = glob(Path :: get('cache-shared') . $this -> generateName($key));

		if(true === is_array($files) && count($files) > 0) {

			$file 		= new File($files[0]);
			$expiration = $this -> extractExpiration($file);

			if($expiration -> time >= time()) {
				return true;
			}

			$file -> delete();
		}

		return false;
	}
725764
public function has($key)
    {
        $keys = is_array($key) ? $key : func_get_args();

        foreach ($keys as $value) {
            if (! $this->offsetExists($value)) {
                return false;
            }
        }

        return true;
    }
52022
public function has($key)
    {
        $parts     = $this->getPath($key);
        $keyExists = true;
        $node      = $this->getFromCache();

        foreach($parts as $part) {
            $part = trim($part);

            if (!is_array($node) || !array_key_exists($part, $node)) {
                $keyExists = false;
                break;
            }

            $node = &$node[$part];
        }

        return ($keyExists);
    }
590745
public function exists($key)
    {
        if ($this->enabled) {
            return !$this->pool->getItem($key)->isMiss();
        } else {
            return false;
        }
    }
727280
public function has(string $key): bool
    {
        return isset($this->data[$key]) || array_key_exists($key, $this->data);
    }
602663
protected function hasKey($key)
    {
        return ($this->mode == self::MODE_INDEXED && $key == '') || \array_key_exists($key, $this->params);
    }
364032
public function offsetExists($key)
    {
        return isset($this->data[$key]) || array_key_exists($key, $this->data);
    }
1346603
public function exists($key) {

        $stmt = $this->connection->query("SELECT `key` FROM ".$this->table." WHERE `key`='{$key}';");
        $res  = $stmt->fetch(\PDO::FETCH_ASSOC);

        return isset($res["key"]);
    }
1339046
public function hasQuery($key)
    {
        $arrayKeys = array_keys($_GET);
        $keys = is_array($key) ? $key : func_get_args();

        foreach ($keys as $value) {
            if (!in_array($value, $arrayKeys) || trim((string)$_GET[$value]) === '') {
                return false;
            }
        }

        return true;
    }
379742
public function exists(string $key) : bool
    {
        $this->checkCallback();
        return isset($this->members[$key]);
    }
566699
public function hasKey(string $key): bool
    {
        return $key && strpos($key, '@@') === false && file_exists($this->getPathFromKey($key));
    }
409768
public static function exists(array $array, $key)
    {
        //
        if (array_key_exists($key, $array)) {
            return true;
        }
        //
        $keys = dot($key);
        //
        foreach ($keys as $key) {
            if (array_key_exists($key, $array)) {
                $array = (array) $array[$key];
                continue;
            } else {
                return false;
            }
        }
        //
        return true;
    }