Check if the $key exists within the post or query bags.

@param string $key The key to check for.
@return bool
350421
public function has($key): bool
    {
        return $this->post->has($key) ?: $this->query->has($key) ?: false;
    }
757897
public function has( $key )
	{
		$key	= !$this->caseSensitive ? strtolower( $key ) : $key;								//  lowercase key if dictionary is not case sensitive
		return array_key_exists( $key, $this->pairs );
	}
609952
public function has($key)
    {
        if ($this->needParser()) {
            $this->treatPutRequest();

            return array_key_exists($key, $_REQUEST);
        }

        return parent::has($key);
    }
759919
protected function exists($key)
    {
        if (!array_key_exists($key, $this->items)) {
            // key not in cache
            return false;
        }

        $expire = $this->items[$key][1];
        if ($expire !== 0 && $expire < time()) {
            // not permanent & already expired
            $this->size -= strlen($this->items[$key][0]);
            unset($this->items[$key]);

            return false;
        }

        $this->lru($key);

        return true;
    }
469164
public function has(string $key): bool
    {
        if (strpos($key, '.') != false) {
            return $this->getNested($key) != null;
        }

        return array_key_exists($key, $this->settings);
    }
636374
public function has($key)
    {
        return (isset($this->headers[$this->normalizeKey($key)])) ? true : false;
    }
743996
public function containsKey($key)
    {
        if (!$this->enabled)
            return false;

        $has_key = false;

        $fetchMethod = $this->apcFuncPrefix.'_fetch';
        $fetchMethod($this->key($key), $has_key);

        // $this->Logger->debug("Cache contains {$key}? " . (($has_key) ? 'TRUE' : 'FALSE'));

        return $has_key;
    }
379742
public function exists(string $key) : bool
    {
        $this->checkCallback();
        return isset($this->members[$key]);
    }
619117
public function exist($key) : bool
    {
        return $this->get($key, false) !== false
               && $this->get($key, true) !== true;
    }
1225151
public function has($key)
    {
        if (!$this->isEnabled()) {
            return false;
        }

        return (null !== eaccelerator_get($this->prefix() . $key));
    }
590745
public function exists($key)
    {
        if ($this->enabled) {
            return !$this->pool->getItem($key)->isMiss();
        } else {
            return false;
        }
    }
888325
function exists($key) {
		$key=$this->fixheader($key);
		return isset($this->headers[$key]);
	}
926924
public function has(string $key): bool
    {
        return $this->customTypes && $this->customTypes->has($key) || array_key_exists($key, $this->types);
    }
266238
public function exists(?string $key = null) : bool
    {
        $key = $this->constructKey($key);

        return $this->parseKey($key, function ($part, $result) {
            return array_key_exists($part, $result);
        });
    }
294186
public function has(?string $key = null) : bool
    {
        $key = $this->constructKey($key);

        return $this->parseKey($key, function ($part, $result) {
            return isset($result[$part]);
        });
    }
1068573
public function containsKey($key)
    {
        if (!$this->enabled)
            return false;

        $has_key = file_exists($this->file($key));

//        $this->Logger->debug("Cache contains {$key}? " . ($has_key) ? 'TRUE' : 'FALSE');

        return $has_key;
    }
132250
public static function check($key)
    {
        if (!self::_tableExists()) {
            return;
        }

        self::autoLoad();
        $model = self::model();

        if (key_exists($key, self::$_data)) {
            return true;
        }

        $query = $model->findByName($key);

        if (!$query->Count()) {
            return false;
        }

        return true;
    }