创建基于NSArray的新的阵列，其包含词典

Question

我有字典的阵列，其从核心数据读取请求的结果与结果类型的NSDictionary：

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

的样品结果的NSDictionaryNSArray看起来如下：

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

什么是最有效的方式来创建（三级）独立阵列endCalYear = 2006，2007，2008; endMonth = 3,9,12和periodLength = 3,6,12从NSArray给出？

谢谢！

Answer 1

您可以使用valueForKey：

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