Can we update the array stored in NSUserDefault - iphone

Question

I am having values stored in an array, and stored that array in NSUserDefault, then i need to update that array can i do so. If then how?

Answer 1

First retrieve the current data.
NSArray *tempNew = [[NSArray alloc]init];
tempNew = [storeData objectForKey:#"accounts"];
[tempArr addObjectsFromArray:tempNew];
Update:
[tempArr addObject:str];
[storeData setObject:tempArr forKey:#"accounts"];

Answer 2

NSUserDefaults is just as an NSDictionary, so you can use the same method of updating a dictionary by setting another object to the key value -setObject:forKey:.
for example when you try below code
NSUserDefaults *usr=[NSUserDefaults standardUserDefaults];
NSArray *arr= [NSArray arrayWithObjects:[NSNumber numberWithInt:1],[NSNumber numberWithInt:2], nil];
[usr setObject:arr forKey:#"num"];
NSLog(#"usr %#",[usr arrayForKey:#"num"]);
NSUserDefaults *usr1=[NSUserDefaults standardUserDefaults];
NSArray *arr= [NSArray arrayWithObjects:[NSNumber numberWithInt:2],[NSNumber
numberWithInt:3], nil];
[usr setObject:arr forKey:#"num"];
NSLog(#"user1 %#",[usr1 arrayForKey:#"num"]);
u will get
usr (
1,
2
)
usr1 (
2,
3
)
in console.

Answer 3

Just re-store the array in the user defaults and call synchronize.
So for example:
Store your array...
NSMutableArray *yourArray = .... // whatever you did to create your data
// store your data in the NSUserDefaults
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:yourArray forKey:#"myArray"];
[defaults synchronize];
... and then some other time somewhere in your app update it!
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
// retrieve your data from the NSUserDefaults
NSMutableArray *yourArray = [defaults objectForKey:#"myArray"];
// edit the data, for example add some object.
[yourArray addObject:someNewObject];
// update the defaults
[defaults setObject:yourArray forKey:#"myArray"];
[defaults synchronize];