Both variants are exactly the same right?
Variant 1:
for(id<MyAwesomeProtocol> obj in [self.instances copy]) {
...
}
Variant 2:
NSArray *instancesCopy = [self.instances copy];
for(id<MyAwesomeProtocol> obj in instancesCopy) {
...
}
Will the copy method [self.instances copy] in variant 1 called multiple times for each loop?
It will only be executed once at the beginning of the loop right? So this makes code like variant 2 pretty unnecessary? Am I right?
I think I got confused because the condition statement in normal for-loop will be executed on each loop. Instead of writing:
for (NSUInteger i = 0; i < [self.instances count]; i++) {
}
It might be better (in some cases) to cache the count once for performance reasons:
for (NSUInteger i = 0, count = [self.instances count]; i < count; i++) {
}
Does this still hold true for LLVM 6.0 (Xcode 6.0, iOS 8.0)? Or will such code optimized by the compiler?
PS: I'm not really sure how to phrase my stupid question title ;)
