cocoa - 使用 nspredicate 使用字典过滤数组失败

Question

我正在尝试使用谓词从 NSMutableArray 中获取 NSDictionary：

NSMutableArray *arr = [NSMutableArray arrayWithArray:[self createArrayFromCSV:savedCSV withDelimiter:delim firstLineContainsKeys:YES]];

// The method «createArrayFromCSV returns an array of dictionaries

NSLog(@"Array %@", [arr objectAtIndex:0]);  // works fine

// spits out: 

// Array {
//     product = "MyProduct";
//     "id_product" = 29;
// }

// idField and idVal are passed to the method

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(%@ == %@)", idField, idVal];

NSLog(@"predicate %@", predicate);

// spits out predicate "id_product" == "29"

NSArray *filtered = [arr filteredArrayUsingPredicate:predicate];

NSLog(@"Filtered %@", filtered);

// Filtered is always empty

任何想法我做错了什么？？？

[已解决] 显然，我把格式字符串弄错了。这有效：

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(%K == %@)", idField, idVal];

根据这篇文章NSPredicate predicateWithFormat 传入属性名称

对于键或键路径，必须使用 @K

Answer 1

显然，我把格式字符串弄错了。这有效：

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(%K == %@)", idField, idVal];

根据这篇文章 NSPredicate predicateWithFormat 传入属性名称

对于键或键路径，必须使用 @K

Answer 2

这对我有用：

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"email contains[c] %@",searchString];

filteredArray = [[NSMutableArray alloc] initWithArray: [[arrayData filteredArrayUsingPredicate:predicate] copy]];