如何检测NSArray中有多少相同的对象

Question

我有一个NSArray,我想知道它有多少特定的对象？

这是我的代码:

NSArray *filter = [[NSArray alloc]initWithObjects:@"1",@"2",@"2",@"3",@"2",@"3", nil];

switch (section) {
      case 0:
          //check how many 1 object is filter array
          return //number of 1 object
          break;
      case 1:
          //check how many 2 object is filter array
          return //number of 2 object
          break;
      case 2:
          //check how many 3 object is filter array
          return //number of 3 object
          break;
}

请指导我.

Answer 1

听起来像你想要使用: NSCountedSet

NSCountedSet *filter = [NSCountedSet setWithObjects:@"1",@"2",@"2",@"3",@"2",@"3", nil];
NSLog(@"%@", @([filter countForObject:@"2"])); // Outputs 3

如果您已经拥有阵列,则可以执行以下操作: [NSCountedSet setWithArray:array]