scala - 带大小写和不带大小写的 zipWithIndex

Question

下面两段代码如何等效？ (案例如何运作)

 list.zipWithIndex.flatMap{ 
     rowAndIndex =>
     rowAndIndex._1.zipWithIndex
}

和

list.zipWithIndex.flatMap {
    case (rowAndIndex, r) =>
     rowAndIndex.zipWithIndex
}

Answer 1

您可能对第二个示例中的错误名称感到困惑。我将其更改为:

list.zipWithIndex.flatMap {
    case (row, index) =>
     row.zipWithIndex
}

这是以下内容的简短版本:

list.zipWithIndex.flatMap { rowAndIndex => 
  rowAndIndex match {
    case (row, index) => row.zipWithIndex
  }
}