iphone - Difference between "self setDoublePicker:nil" and "self.doublePicker = nil" -

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as title explained, if control drag component in xib file towards .h file conveniently create outlet, doublepicker or else, xcode create statement in viewdidunloaded: method this:

[self setdoublepicker:nil];

what difference between and:

self.doublepicker = nil;

which 1 performs better?

foo *foo = [[foo alloc] init]; foo.bar = yes; [foo setbar:yes]; 

the last 2 lines compile same. thing changes if property has getter and/or setter attribute specified; however, change message gets sent, not whether message sent:

if ([someview isempty]) { /* ... */ } if (someview.empty) { /* ... */ } 

both lines gives same result. . once refere 1 better understanding dot notation.