我有一个字典的NSMutableArray。dic1=["user":"Smith","points":12,"lastPoints":4,online:3MonthsAgo(NSDate)]dic2=["user":"Mike","points":22,"lastPoints":3,online:2MonthsAgo(NSDate)]dic3=["user":"Mark","points":22,"lastRank":5,online:now(NSDate)]dic4=["user":"Jay","points":16,"lastPoints":2,online:2minutes(N