objective-c - 数组中字典的总和

Question

我有一个包含 NSDictionary 列表的 NSArray。喜欢:

NSArray *array = ...;
NSDictionary *item = [array objectAtIndex:0];
NSLog (@"quantity: %@", [item objectForKey: @"quantity"]);

如何对数组的所有字典中包含的所有数量求和？

Answer 1

我觉得你可以试试KVC

NSMutableArray *goods = [[NSMutableArray alloc] init];
NSString *key = @"quantity";

[goods addObject:@{key:@(1)}];

[goods addObject:@{key:@(2)}];

[goods addObject:@{key:@(3)}];

NSNumber *sum = [goods valueForKeyPath:@"@sum.quantity"];
NSLog(@"sum = %@", sum);