Remove objects using NSPredicate

Question

I have the folloving dictionary which has many sub dictionaries. How can I remove objects where isChanged = 1 from parent dictionary using NSPredicate

Answer 1

I solved my problem in the following way:

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"isChanged == %d", 1];

NSArray *allObjs = [parentDict.allValues filteredArrayUsingPredicate:predicate];

[allObjs enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    NSMutableArray *keys = [[NSMutableArray alloc] initWithCapacity:0];
    [keys setArray:[parentDict allKeysForObject:obj]];
    [parentDict removeObjectsForKeys:keys];
    [keys release];
}];

Answer 2

As a simple alternative to using NSPredicate, you can use the NSDictionary's built in keysOfEntriesPassingTest: This answer assumes "isChanged" is an NSString and the value 0 or 1 is an NSNumber:

NSSet *theSet = [dict keysOfEntriesPassingTest:^(id key, id obj, BOOL *stop) {
    return [obj[@"isChanged"] isEqualToNumber: @1];
}];

The returned set is a list of keys that pass the test. From there, you could remove all that matched with:

[dict removeObjectsForKeys:[theSet allObjects]];

Answer 3

when you have array of dictionary than you can remove selected category's data using NSPredicate

here is code

NSString *selectedCategory = @"1";

//filter array by category using predicate
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"isChanged == %@", selectedCategory];

NSArray *filteredArray = [yourAry filteredArrayUsingPredicate:predicate];

[yourAry removeObject:[filteredArray objectAtIndex:0]];  

But in your problem data is not in array it is in dictionary

your data should be in this format

(
 {
     cellHeight = 437;
     isChanged = 1;
 },
 {
     cellHeight = 145;
     isChanged = 0;
 },
 {
     cellHeight = 114;
     isChanged = 1;
 }
 )