Question

i am adding values to NSUserDefaults at run time and making the keys as [NSString stringWithFormat:@"decrement%@",course_id];

i am setting the objects one by one is there any way i can get all the userdefaults object whose key start with “decrement”?

or i have to go in a loop and get object by making exact key one by one?

Note :- i accept down vote as an healthy way of criticism but do write the reason so that i can improve.

Answer 1

You can get all dictionary key of NSUserDefaults like this:

 NSArray *arrKeys = [[[NSUserDefaults standardUserDefaults] dictionaryRepresentation] allKeys]

Now use NSPredicate for finding [NSString stringWithFormat:@”decrement%@”,course_id]; value in arrKeys

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(SELF like %@)",@"decrement"];
NSArray *keysLikeDecrement =
[arrKeys filteredArrayUsingPredicate:predicate];

NSPredicate *aPredicate =
[NSPredicate predicateWithFormat:@"SELF beginswith 'decrement'"];
NSArray *beginWithDecrement =
[arrKeys filteredArrayUsingPredicate:aPredicate];

NSPredicate *bPredicate =
[NSPredicate predicateWithFormat:@"SELF contains 'decrement'"];
NSArray *containsWithDecrement =[arrKeys filterUsingPredicate:bPredicate];