nspredicate

问题 I am new to NSPredicates, but I know the basics. This is how my predicate looks now: [NSPredicate predicateWithFormat:@"name contains[c] %@", searchText]; What I want to do, is to be able to create a predicate like this (Pseudo code): NSPredicate *myPredicate = [NSPredicate predicateWithBaseString:@"name contains[c] _ARGUMENT_"]; And then use it in, for example a loop (pseudo code): for(NSString *searchString in self.allStrings) { NSPredicate *myNewPredicate = [myPredicate

问题 I have an array with file names and I want to find all the names that end with e.g. 00001.trc when traceNum is 1. I tried this: NSPredicate *tracePredicate = [NSPredicate predicateWithFormat:@"SELF ENDSWITH \"%05d.trc\"", traceNum]; and my predicate was SELF ENDSWITH "%05d.trc" instead of SELF ENDSWITH "00001.trc" I tried this: NSPredicate *tracePredicate = [NSPredicate predicateWithFormat:@"SELF ENDSWITH %@%05d.trc%@", @"\"", traceNum, @"\""]; and I got an exception: Unable to parse the

问题 I have a simple method that uses NSPredicate to return the number of rows where comments.length > 0. Problem is, I found that when the Comment column starts with + - * or /, the length property always evaluates to 0, and thus the row is excluded from the count. I opened the table in SQLite browser and verified the column is a VARCHAR. Using a SQLite query to check string length works just fine (LENGTH(ZComments) > 0), so this must be a CoreData issue. Here is my function... -(int

问题 I'm using a SQLite persistent store. I have a NSManagedObject class Den with a to-many relationship Bear . Bear has several fields: Bear: breed color age ... When I am building fetch requests for my Den objects, I can filter to objects that have a related Bear with a certain field value: NSPredicate *hasGrizzlyPred = [NSPredicate predicateWithFormat:@"ANY Bear.breed == 'grizzly'"]; Or I can just as easily search for a Den that has a brown bear: NSPredicate *hasBrownBearPred = [NSPredicate

问题 I have an array which consists of several NSDictionaries with the keys: NSString *name NSString *ID NSDictionary *phoneNumbersDict Now I want to filter this array to find the one which has the phoneNumbersDict key @"keyIAmLookingFor" and the value @"valueIAmLookingFor" . NSMutableArray *addressBookPhoneIndividuals = [NSMutableArray array]; for (int i = 0; i < x; i++) { [addressBookPhoneIndividuals addObject:@{ @"name" : @"...", @"ID" : @"...", @"phoneNumbers" : @{...} }]; } 回答1: NSString

问题 Newbie Questions, I have 3 Class, 3 of them are subclass from NSOBject. Collection Class , have 2 properties, masterSong as NSMutableSet (strong, nonatomic) and listOfPlaylists as NSMutableArray (strong, nonatomic) Playlist Class Have 2 properties, playListName as NSString (copy, nonatomic) and songList as NSMutableArray (strong, nonatomic) 3 . Song Class Have 4 properties: title,artist,album, playtime as NSString (copy, nonatomic). masterSong will contain Song object, and listOfPlaylist will

问题 My current version for get @min or @max value is: for (NSManagedObject *destination in allSpecifics) { [allRates addObject:[destination valueForKey:@"rate"]]; } NSExpression *arrayExpression = [NSExpression expressionForConstantValue: allRates]; NSArray *argumentArray = [NSArray arrayWithObject: arrayExpression]; NSExpression* expression = [NSExpression expressionForFunction:@"min:" arguments:argumentArray]; id result = [expression expressionValueWithObject: nil context: nil]; NSNumber

问题 I have an NSMutableArray containing TBPosts that I would like to filter in descending order according to the commentsCount and likesCount of the TBPost . Initially, the first object in the filtered array will be the object with the largest number of comments and likes, which can be worked out by adding the two together. So I tried the following query and receive an Unable to Parse error. Please can you tell me where I am going wrong? [posts filterUsingPredicate:[NSPredicate

问题 I'm trying to filter an array of objects that essentially form a tree-style graph. what i want to do is to filter out all objects from this array whose visible property is NO, or if its parent/grandparent/etc visible property is true (child objects can have the visible property be YES while its parent can be NO). I'm unclear as to how i would go about this using NSPredicate syntax to keep searching the parent node until there are no parents or the visible property is found. Is there any way

问题 [filteredArray filterUsingPredicate: [NSPredicate predicateWithFormat:@"self BEGINSWITH[cd] %@", searchText]]; filteredArray contains simple NSStrings. [hello, my, get, up, seven, etc...]; It will give all strings that begin with searchText . But if string will be a combination of words like "my name is", and searchText = name . What would a NSPredicate look like to achieve this? UPDATE: And how would it have to be if i want to a result with searchText = name , but not with searchText = ame ?