2014/10/15 下午 10:08:04

iphone Programming Glossary: emailaddress

Distinct Count via Core Data, NSExpression Into NSFetchedResultsController

http://stackoverflow.com/questions/9157436/distinct-count-via-core-data-nsexpression-into-nsfetchedresultscontroller

NSExpression as you originally proposed in my contrived example I have an entity called Person with a property called emailAddress that I wish to get the count for. NSPropertyDescription propDesc model entitiesByName objectForKey @ Person propertiesByName.. count for. NSPropertyDescription propDesc model entitiesByName objectForKey @ Person propertiesByName objectForKey @ emailAddress NSExpression emailExpr NSExpression expressionForKeyPath @ emailAddress NSExpression countExpr NSExpression expressionForFunction.. @ Person propertiesByName objectForKey @ emailAddress NSExpression emailExpr NSExpression expressionForKeyPath @ emailAddress NSExpression countExpr NSExpression expressionForFunction @ count arguments NSArray arrayWithObject emailExpr NSExpressionDescription..