迭代字典

Question

我正在尝试迭代一个NSMutableDictionary，我似乎无法得到我想要的东西。我有一个字典将字符串映射到颜色，如此...

squareColors = [NSMutableDictionary dictionaryWithObjects: [NSMutableArray arrayWithObjects:
                                                                [NSNumber numberWithInt:0],
                                                                [NSNumber numberWithInt:0],
                                                                [NSNumber numberWithInt:0],
                                                                [NSNumber numberWithInt:0],
                                                                [NSNumber numberWithInt:0],
                                                                nil]

                                                      forKeys: [NSMutableArray arrayWithObjects:
                                                                @"yellow",
                                                                @"blue",
                                                                @"green",
                                                                @"purple",
                                                                @"orange",
                                                                nil]];

随着时间的推移，每个条目的价值都会增加。每隔一段时间我就要查看字典并选择计数最多的颜色。我怎么能这样做？这是我正在尝试的，但我不熟悉块。

__block int mostSquares = 0;
__block NSString* color = @"";
/* Look through the dictionary to find the color with the most number of squares */
[squareColors enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
   NSLog(@"%@ => %@", key, obj);
   NSInteger count = [key integerValue];
   if (count > mostSquares)
   {
        color = key;
        mostSquares = count;
   }
}];

Answer 1

您的代码中有一个非常简单的错误。这一行：

NSInteger count = [key integerValue];

应该是：

NSInteger count = [obj integerValue];

'key'是颜色名称，obj是数字。正如您所知，每次迭代都会count设置为0，因为在非数字字符串上调用integerValue会为您提供0。

Answer 2

使用您的示例的简单解决方案：

NSMutableArray *arrayNumbers = [NSMutableArray arrayWithObjects:
                                [NSNumber numberWithInt:0],
                                [NSNumber numberWithInt:1],
                                [NSNumber numberWithInt:2],
                                [NSNumber numberWithInt:6],
                                [NSNumber numberWithInt:4],
                                nil];
NSMutableArray *arrayColours =  [NSMutableArray arrayWithObjects:
                                 @"yellow",
                                 @"blue",
                                 @"green",
                                 @"purple",
                                 @"orange",
                                 nil];
NSMutableDictionary *squareColors = [NSMutableDictionary dictionaryWithObjects:arrayNumbers
                                                                       forKeys:arrayColours];
NSUInteger indexOfArray = [arrayNumbers indexOfObject:[arrayNumbers valueForKeyPath:@"@max.intValue"]];
NSLog (@"Colour with largest value is %@", [arrayColours objectAtIndex:indexOfArray]);

Answer 3

您可以将密钥存储到数组中并使用该数组进行迭代吗？这可能是最有效的解决方案，因为无论如何你都需要知道每个键。