iPhone CoreData - How to fetch managed objects, and sorting them ignoring case?

问题

Does anyone know how to fetch some results sorting them alphabetically but ignoring case?

回答1:

Thank you for your reply, but I need to sort the result of a simple "query" ignoring case. Your suggestion applies for searching and comparing.

SQL speaking, I need an ORDER BY firstName ASC, and this command must be case insensitive for my usage.

I have done some Googling and I ended reading the NSSortDescriptor Class reference, and I could find the answer for my question. The solution is setting a selector to the sort descriptor as follow:

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"firstName" ascending:YES selector:@selector(caseInsensitiveCompare:)];

I hope it will be useful for more people.

回答2:

If the app is localized in several languages, please consider using the localizedCaseInsensitiveCompare: selector instead of caseInsensitiveCompare. It will have the effect to avoid the letter 'é' to be after the letter 'e'.

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"firstName" ascending:YES selector:@selector(localizedCaseInsensitiveCompare:)];

回答3:

Check out the NSPredicate programming guide, but basically use [c] to ignore case:

@"firstName BEGINSWITH[c] $FIRST_NAME"

回答4:

Swift Version:

let sortDescriptor = NSSortDescriptor(key: "firstName", ascending: true, selector: #selector(NSString.localizedCaseInsensitiveCompare))

来源：https://stackoverflow.com/questions/2013158/iphone-coredata-how-to-fetch-managed-objects-and-sorting-them-ignoring-case