Question

考虑一下代码：

println("func")
println(builderFor)

private val LineCount: Int = 10000/*000*/
private val SymbolCount: Int = 100

private def builderFor: String = {
  val stBuilder = new StringBuilder()
  for (line <- 1 to LineCount) {
    for (symbol <- 1 to SymbolCount) {
        stBuilder.append("z" * symbol)
      }
  }
  stBuilder.toString()
}

它打印出来：

func

我已将stBuilder.append("z" * symbol)替换为println("ok")并获得了相同的结果。它接缝scala Range没有迭代，但为什么？

Answer 1

如果这是App或def main(args: String*): Unit的正文，则问题是您之前致电println(builderFor)

private val LineCount: Int = 10000/*000*/
private val SymbolCount: Int = 100

代码LineCount和SymbolCount中此pint的

未初始化，因此0。只需向下移动两行即可。顺便说一下，如果你想要有z的行，那么你需要在你的行中添加换行符。

println("func")

private val LineCount: Int = 10
private val SymbolCount: Int = 10

println(builderFor)

private def builderFor: String = {
  val stBuilder = new StringBuilder()
  for (line <- 1 to LineCount) {
    for (symbol <- 1 to SymbolCount) {
      stBuilder.append("z" * symbol + "\n")
    }
  }
  stBuilder.toString()
}

为什么scala Range在foreach期间不会迭代？

1 个答案: