parameter key (case insensitive)
result destination; will be changed only if a value exists for key
will be changed to true if a value exists for key (even if it is empty or not an unsigned decimal integer number)
true on success or false if either no value exists for key or the value is empty or not an unsigned decimal integer number or.
Behaves like regular associative array indexing using key as key.
Obtains the parameter value corresponding to key which is expected to be an unsigned decimal integer number and not empty. key must be one of the parameter keys passed on instantiation or added by a subclass.