我有一个NSMutableArray
,其对象类型为NSMutableDictionary
,
NSMutableDictionary
包含2个键
- 航空公司(字符串)
-Rating(整数)
我有NSMutableArray
所有对象,我需要的是总结所有航空公司重复对象的评级,例如:
Airline Rating
A 2
B 3
B 4
C 5
最终结果数组将是A = 2,C = 5和B的总和等于7.
到目前为止我的代码:
for (int i = 0; i < arrayMealRating.count; ++i) {
NSMutableDictionary *item = [arrayMealRating objectAtIndex:i];
NSLog(@"item=%@",item);
for (int j = i+1; j < arrayMealRating.count; ++j)
{
if ([[item valueForKey:@"Airline"] isEqualToString:[arrayMealRating objectAtIndex:j]]){
NSMutableDictionary *item = [arrayMealRating objectAtIndex:j];
NSMutableDictionary *item1 = [arrayMealRating objectAtIndex:i];
NSInteger auxCount = [[item valueForKey:@"setMealRating"] integerValue] + [[item1 valueForKey:@"setMealRating"] integerValue];
NSMutableDictionary *aux = [NSMutableDictionary dictionaryWithObjectsAndKeys:[item valueForKey:@"Airline"], @"Airline"
,[NSString stringWithFormat:@"%d",auxCount], @"setMealRating"
,nil];
NSLog(@"aux=%@",aux);
[arrayMealRating replaceObjectAtIndex:i withObject:aux];
}
}
}
我知道有点乱,但我不知道如何使用NSMutableDictionary
,任何帮助将不胜感激,在此先感谢!
答案 0 :(得分:5)
如果您不想更改存储数据的方式,那么您将如何使用key-value coding进行更改。下面是@distinctUnionOfObjects and @sum文档的直接链接。
// Get all the airline names with no duplicates using the KVC @distinctUnionOfObjects collection operator
NSArray *airlineNames = [arrayMealRating valueForKeyPath:@"@distinctUnionOfObjects.Airline"];
// Loop through all the airlines
for (NSString *airline in airlineNames) {
// Get an array of all the dictionaries for the current airline
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(Airline == %@)", airline];
NSArray *airlineMealRating = [arrayMealRating filteredArrayUsingPredicate:predicate];
// Get the sum of all the ratings using KVC @sum collection operator
NSNumber *rating = [airlineMealRating valueForKeyPath:@"@sum.Rating"];
NSLog(@"%@: %@", airline, rating);
}
这给出了以下输出
A: 2
B: 7
C: 5
答案 1 :(得分:1)
如果可能的话,我建议完全重新设计。
创建课程Airline
@interface Airline : NSObject
@property (strong, nonatomic) NSString *name;
@property (strong, nonatomic) NSMutableArray *mealRatings;
- (void)addMealRating:(float)rating;
- (float)sumOfMealRatings;
@end
@implementation
- (id)initWithName:(NSString *)pName
{
self = [super init];
if (self)
{
self.name = pName;
self.mealRatings = [NSMutableArray array];
}
return self;
}
- (void)addMealRating:(float)rating
{
[self.mealRatings addObject:@(rating)];
}
- (float)sumOfRatings
{
float sum = 0;
for (NSNumber *rating in self.mealRatings)
{
sum += [rating floatValue];
}
}
@end
然后在“主要类”中,您只需拥有NSArray
个Airline
个实例的实例。它可能需要您更改一些现有代码,但我认为从长远来看它可以节省您的时间和麻烦。也许您稍后会认识到,您想要为您的航空公司添加其他属性。字典是一种繁琐的方法。
答案 2 :(得分:1)
@try this
NSMutableArray *myArray = [[NSMutableArray alloc] initWithCapacity:4];
NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
[dict setValue:[NSNumber numberWithInteger:2] forKey:@"A"];
[myArray addObject:dict];
NSMutableDictionary *dict2 = [[NSMutableDictionary alloc] init];
[dict2 setValue:[NSNumber numberWithInteger:3] forKey:@"B"];
[myArray addObject:dict2];
NSMutableDictionary *dict3 = [[NSMutableDictionary alloc] init];
[dict3 setValue:[NSNumber numberWithInteger:4] forKey:@"B"];
[myArray addObject:dict3];
NSMutableDictionary *dict4 = [[NSMutableDictionary alloc] init];
[dict4 setValue:[NSNumber numberWithInteger:5] forKey:@"D"];
[myArray addObject:dict4];
NSMutableDictionary *resultDictionary = [[NSMutableDictionary alloc] init];
for(NSMutableDictionary *dictionary in myArray)
{
NSString *key = [[dictionary allKeys] objectAtIndex:0];
NSInteger previousValue = [[resultDictionary objectForKey:key] integerValue];
NSInteger value = [[dictionary objectForKey:key] integerValue];
previousValue += value;
[resultDictionary setObject:[NSNumber numberWithInteger:previousValue] forKey:key];
}
for(NSString *key in resultDictionary)
{
NSLog(@"value for key = %@ = %d",key, [[resultDictionary valueForKey:key] integerValue]);
}