nspredicate

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I'm saving CLPlacemark in Core data using NSValueTransformer . (so it's saved as NSData ) However I've come to a point where I need to filter the saved objects based on another CLPlacemark object. I've tried this, it doesn't work: NSExpression *exprPath = [NSExpression expressionForKeyPath:@"placemark"]; NSExpression *exprKeyword = [NSExpression expressionForConstantValue:[NSKeyedArchiver archivedDataWithRootObject:placemark]]; NSPredicate *predicate = [NSComparisonPredicate predicateWithLeftExpression:exprPath rightExpression:exprKeyword

I'm trying to write a query for the find-as-you-type search bar. What I want to do is query "Kind", and return any Kinds for which there is a LocalName with ('name' LIKE %@ AND localeIdentifier == %@). If I'm only searching the names (so ignoring the localeIdentifier), I could do something like this: ANY localized.name LIKE %@ What I want is something more like ANY localized.(name LIKE %@ AND localeIdentifier == %@) To sum up, searching "Kind", any one item in the to-many relationship "localized" should match both name and localeIdentifier. Any ideas for the correct syntax of this? What you

I have a large number of strings that I'm searching to see if a given substring exists. It seems there are two reasonable ways to do this. Option 1: Use the NSString method rangeOfSubstring and test whether .location exists: NSRange range = [string rangeOfSubstring:substring]; return (range.location != NSNotFound); Option 2. Use the NSPredicate syntax CONTAINS : NSPredicate *regex = [NSPredicate predicateWithFormat:@"SELF CONTAINS %@", substring]; return ([regex evaluateWithObject:string] == YES) Which method is better, or is there a good Option 3 that I'm completely missing? No, I'm not sure

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Is this how I'm supposed to pass a Date to NSPredicate.init(format predicateFormat: String, arguments argList: CVaListPointer) . let endDate = Date() NSPredicate(format: "endDate == %@", endDate as CVarArg) It looks kinda clumsy, and I suspect I'm doing something wrong. 回答1: The %@ format expect a Foundation object as argument, compare "Predicate Format String Syntax" in the "Predicate Programming Guide". Therefore you have to cast the overlay type Date back to its Foundation counterpart NSDate : let endDate = Date() let pred = NSPredicate

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: This question already has an answer here: Creating NSPredicate dynamically by setting the key programmatically 2 answers I am trying to write a NSPredicate to fetch rows with my_column value with this string " 193e00a75148b4006a451452c618ccec " and I get the below crash. Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unable to parse the format string "my_column=193e00a75148b4006a451452c618ccec"' My predicate statement fetchRequest.predicate=[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"%@==\"

I'm trying to make sections in a table view based on the alphabet and sort my entries alphabetically under these sections. I have collected the first letter in every entry of bandsArray in bandsArrayIndex and I'm now trying to use NSPredicate to count how many of each letter there are. I'm doing this by following this guide . They are using an NSArray and I'm using an NSDictionary and can't seem to get it to work. Can anyone help me out? The application crashes when trying to show the view with the table view in it. In Debugger Console the following error is shown: * Terminating app due to