ios 数组里面的字典，

ios 数组里面的字典，然后按照某个字典排序，比如按照价格从低到高排序实现

NSDictionary *car1 = @{
@"make": @"Volkswagen",
@"model": @"Golf",
@"price": [NSDecimalNumber decimalNumberWithString:@"18750.00"]
};

NSDictionary *car2 = @{
@"make": @"Volkswagen",
@"model": @"Eos",
@"price": [NSDecimalNumber decimalNumberWithString:@"35820.00"]
};

NSDictionary *car3 = @{
@"make": @"Volkswagen",
@"model": @"Jetta A5",
@"price": [NSDecimalNumber decimalNumberWithString:@"16675.00"]
};

NSDictionary *car4 = @{
@"make": @"Volkswagen",
@"model": @"Jetta A4",
@"price": [NSDecimalNumber decimalNumberWithString:@"16675.00"]
};

NSMutableArray *cars = [NSMutableArray arrayWithObjects:
car1, car2, car3, car4, nil];

NSSortDescriptor *priceDescriptor = [NSSortDescriptor
sortDescriptorWithKey:@"price"
ascending:YES
selector:@selector(compare:)];
NSSortDescriptor *modelDescriptor = [NSSortDescriptor
sortDescriptorWithKey:@"model"
ascending:YES
selector:@selector(caseInsensitiveCompare:)];

NSArray *descriptors = @[priceDescriptor, modelDescriptor];
[cars sortUsingDescriptors:descriptors];
NSLog(@"%@", cars);