Question

In UserDefault file I have six fields. I want to persist two field always and reset four other field in some scenario. What is best approach to handle this?

Answer 1

If your want the four field to reset with their default values.

And the default value may be an empty string ,

 #define KDefault @"" 
 NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
 if (standardUserDefaults)
 {
        [standardUserDefaults setObject:KDefault forKey:@"first"];
        [standardUserDefaults setObject:KDefault forKey:@"two"];
        [standardUserDefaults setObject:KDefault forKey:@"third"];
        [standardUserDefaults setObject:KDefault forKey:@"four"];
        [standardUserDefaults synchronize];
 }

Edited:
For removing field rather than resetting: Use the below

        [standardUserDefaults removeObjectForKey:@"first"];
        [standardUserDefaults removeObjectForKey:@"two"];
        [standardUserDefaults removeObjectForKey:@"third"];
        [standardUserDefaults removeObjectForKey:@"four"];
        [standardUserDefaults synchronize];