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PONSPredicate for multiple matches in NSFetchRequest
 

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    <p>First off: sorry if the title isn't very clear, I couldn't quite put my question into short words!</p> <p>Please consider the following scenario:<br> - You are using Core Data for storing objects<br> - You want to fetch objects from your context<br> - You want to include a predicate to only fetch objects with certain properties<br> - You have an NSDictionary containing key-value pairs where the key represents the property name and the value represents the desired value to match against</p> <p><strong>How is best to achieve this?</strong></p> <p>I currently have the following, which is a quick and probably inefficient way of achieving this:</p> <pre><code>NSDictionary *attributes = [NSDictionary dictionaryWithObjects: [NSArray arrayWithObjects:@"value1", @"value2", nil] forKeys: [NSArray arrayWithObjects:@"attr1", @"attr2", nil] ]; // Build predicate format NSString *predicate = @""; NSMutableArray *predicateArguments = [[NSMutableArray alloc] init]; int index = 0; for (NSString *key in attributes) { NSString *value = [attributes objectForKey: key]; predicate = [predicate stringByAppendingFormat: @"(%@ = %@) %@", key, @"%@", index == [attributes count]-1 ? @"" : @"AND "]; [predicateArguments addObject: value]; index++; } NSPredicate *matchAttributes = [NSPredicate predicateWithFormat:predicate argumentArray:predicateArguments]; </code></pre> <p>--</p> <p><strong>Is there a shorter or more efficient way of achieving this predicate?</strong></p> <p>Please be aware that block predicates are not an option due to not being supported with NSFetchRequest (Core Data)</p>
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