Question

I am a bit confused when working with objective-c. This part in particular confuses me a lot.

What is the purpose and/ or difference between writing code like this …

object = [object method];

and

[object method];

Learning objective-c up until now, I always assumed that I could do something like this..

say I had already created this..

NSString *object = [[NSString alloc]initWithFormat:@"%@"];

then I could do what I want with that like so..

[object applyAnyMethodHere];

but now I’m seeing things like this ..

object = [object applyAnyMethodHere];

What is the difference between these two?

Answer 1

The first one (object = [object method];) is an assignment of whatever method returns.

The second one ([object method];) is just calling the method without paying attention to its return value (if any).

The third (NSString *object = [[NSString alloc]initWithFormat:@"@"]) declares variable and assigns the return value of the initWithFormat method called on the return value of the alloc class method.