Question

Is there a difference in speed between the following two cases:

A:

userName=[[NSUserDefaults standardUserDefaults] objectForKey:@"userName"];
userEmail=[[NSUserDefaults standardUserDefaults] objectForKey:@"userEmail"];
userId=[[[NSUserDefaults standardUserDefaults] objectForKey:@"userId"] intValue];

B:

userDictionary=[[NSUserDefaults standardUserDefaults] objectForKey:@"userDictionary"];
userName=[userDictionary objectForKey:@"name"];
userEmail=...etc...

Even though differences in speed might be extremely small, technically, are there performance differences?

Answer 1

C is fastest.

C:

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
userName=[defaults objectForKey:@"userName"];
userEmail=[defaults objectForKey:@"userEmail"];
userId=[[defaults objectForKey:@"userId"] intValue];

No sense calling the same method over and over, when you can cache the result locally and reuse it. A method invocation is always going to be slower than accessing a local variable.