scala中 _ reduce groupByKey reduceByKey...用法记录

1: 若是变量是List的话，_ 就至关于List变量每个元素python scala> List((1,2),(5,9)).filter(_._1>1) res5: List[(Int, Int)] = List((5,9)) scala> List((1,2),(5,9)).filter(_._2>1) res6: List[(Int, Int)] = List((1,2), (5,9))

>>阅读原文<<