Question

我有一系列字典，看起来像这样：

    @[@{@"object" : @"circle", @"total" : @12},
      @{@"object" : @"square", @"total" : @7},
      @{@"object" : @"triangle", @"total" : @4},
    ];

我想将其展平为字典，其中键是对象，值是总数：

    @{@"circle" : @12,
      @"square" : @7,
      @"triangle" : @4,
    };

有没有办法做到这一点，除了遍历数组，并映射键？

NSMutableDictionary *objects = [[NSMutableDictionary alloc] init];
for (NSDictionary *object in array)
{
    [objects setObject:object[@"total"] forKey:object[@"object"];
}

如果没有其他方法使用Objective C，那么如何在Swift中编写转换？

Answer 1

一种方法是使用KVC：

NSArray* array = @[@{@"object" : @"circle", @"total" : @12},
    @{@"object" : @"square", @"total" : @7},
    @{@"object" : @"triangle", @"total" : @4},
];
NSArray* objects = [array valueForKeyPath:@"object"];
NSArray* totals = [array valueForKeyPath:@"total"];
NSDictionary* final = [[NSDictionary alloc] initWithObjects:totals forKeys:objects];

Answer 2

对swift的转变如下：

var array = [[String : String]](); // Let this be your array
var requiredDictionary = [String : String](); //be your required dictionary
for object in array {
    let key = object["object"]
    requiredDictionary[key!] = object["total"];
}

是否有更好的方法来压缩NSArray的NSArary？

2 个答案: