Filter NSArray using NSPredicate [closed]

Question

I have an array which contains strings. Some of these string might be empty (@""). How does the predicate have to look like so that it filters the array and returns a new one containing only non empty strings:

Array A: {"A","B","","D"} -> FILTER -> Array B: {"A","B","D"}

and it should also return this:

Array A: {"","","",""} -> FILTER -> Array B: {}

Answer 1

Use predicate SELF != '' if you are filtering just array of NSStrings. This matches every NSString which is not exactly equal to empty string.

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF != ''"];
NSArray *filteredArray = [array filteredArrayUsingPredicate:predicate];

Example code:

NSArray *array = @[@"A", @"B", @"", @"C", @"", @"D"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF != ''"];
NSArray *filteredArray = [array filteredArrayUsingPredicate:predicate];
NSLog(@"Input array: %@\nFiltered array: %@", [array componentsJoinedByString:@","], [filteredArray componentsJoinedByString:@","]);

Gives this output

Input array: A,B,,C,,D
Filtered array: A,B,C,D

Edit: Joris Kluivers posted solution with predicate format length > 0. This is probably better solution just for removing empty string as it will probably be much faster.