How to assign empty value to NSData not NULL value?

Question

How to assign empty value to an NSData not NULL value ?

I didn't want to assign null nor nil. I wanted empty value not like the code below.

NSData* variable = NULL; // not even assigning to nil
NSData* variable = nil;

Answer 1

NSData *variable = [[NSData alloc] init];
// don't forget to release if not using ARC.