基于包含字典的NSArray创建新数组

Question

我有一系列字典，这些字典来自结果类型为NSDictionary的核心数据提取请求：

request.resultType = NSDictionaryResultType;
request.returnsDistinctResults = YES;
request.propertiesToFetch = @[@"endCalYear",@"endMonth",@"periodLength"];

NSArray的示例结果NSDictionary如下所示：

{
    endCalYear = 2007;
    endMonth = 12;
    periodLength = 12;
},
{
    endCalYear = 2006;
    endMonth = 9;
    periodLength = 3;
},
{
    endCalYear = 2006;
    endMonth = 6;
    periodLength = 3;
},
{
    endCalYear = 2006;
    endMonth = 3;
    periodLength = 3;
}

创建（三个）单独数组的最有效方法是什么？ endCalYear = 2006,2007,2008;来自NSArray的 endMonth = 3,9,12和 periodLength = 3,6,12？

谢谢！

Answer 1

您可以使用valueForKey：

NSArray *endCalYearArray = [resultArray valueForKey:@"endCalYear"];