ios 不包含特定字符串的 NSPredicate 查询
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NSPredicate query for not containing a specific string
提问by sangony
Looked high and low for this one but can't find my answer. I am looking to query core data for all records which are NOT equal to a specified string. For example, all records which are not equal to the current session ID. I have tried these to no avail:
看了这个高低，但找不到我的答案。我希望查询所有不等于指定字符串的记录的核心数据。例如，所有不等于当前会话 ID 的记录。我试过这些都无济于事：
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"listingID != %@", [sitListingID objectAtIndex:i]];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%@ NOT CONTAINS[cd] %@",@"listingID", [sitListingID objectAtIndex:i]];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%@ NOT CONTAINS %@",@"listingID", [sitListingID objectAtIndex:i]];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"listingID NOT like %@", [sitListingID objectAtIndex:i]];
Nothing works.HEEEEELP!!! ----------------------------------------------------- more code
什么都不起作用。嘿嘿！！！-------------------------------------------------- --- 更多代码
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"ListingRecord" inManagedObjectContext:context];
[request setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"sessionID <> %@", uniqueSessionListings];
[request setPredicate:predicate];
NSError *error = nil;
NSMutableArray *mutableFetchResults = [[context executeFetchRequest:request error:&error] mutableCopy];
回答by Martin R
Your first predicate
你的第一个谓词
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"listingID != %@", sessionID];
should work to find all records where the attribute listingIDis not equal to sessionID(provided that listingIDand sessionIDhave the same type).
应该可以找到属性listingID不等于的所有记录sessionID（前提是listingID并且sessionID具有相同的类型）。
If both are strings and you want to find all records where listingIDdoes not containthe string sessionIDas a substring, then this predicate should work:
如果两者都是字符串，并且您想查找listingID不包含字符串sessionID作为子字符串的所有记录，则此谓词应该有效：
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"NOT (listingID CONTAINS %@)", sessionID];
Use "CONTAINS[cd]" if the string comparison should be done case and diacritical insensitive.
使用“contains [CD]”如果字符串比较应该做的事情况和变音不区分大小写。
NOTE: You can specify the attribute name as an argument, but then you must use %Kinstead of %@as format:
注意：您可以将属性名称指定为参数，但您必须使用%K代替%@格式：
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"NOT (%K CONTAINS %@)", @"listingID", sessionID];
