NSPredicate that is the equivalent of SQL's LIKE
I'm 开发者_如何学JAVAlooking for a way to use NSPredicate
to set a LIKE
condition to fetch objects. In addition to that, an OR
would be useful as well. I'm trying to do something where if a user searches "James" I can write an NSPredicate
that will do the equivalent of:
select * from users where firstname LIKE '%James%' OR lastname LIKE '%James%';
NSString *_mySearchKey = @"James";
NSPredicate *_myPredicate = [NSPredicate predicateWithFormat:@"(firstname CONTAINS[cd] %@) OR (lastname CONTAINS[cd] %@)", _mySearchKey, _mySearchKey];
The CONTAINS
operator will certainly work just fine. If you're looking for a more direct correlation, then you can also use the LIKE operator (*
= 0 or more characters, ?
= 1 character):
NSString *_mySearchKey = @"James";
NSPredicate *_myPredicate = [NSPredicate predicateWithFormat:@"firstname LIKE '*%1$@*' OR lastname LIKE '*%1$@*'", _mySearchKey];
For reference:
https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/Predicates/Articles/pSyntax.html#//apple_ref/doc/uid/TP40001795-215868
Another possibility
@"firstname beginswith[c] James"
As a nice alternative to contains
Sometimes contains isn't always the right answer
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