Question

我正在尝试以块的形式读取输入流：

import scala.io.Source

// val in = Source.stdin.mkString("")
val in = Source.fromFile("/shared/american.txt").getLines.mkString("")
var ptr = 0
val out = Stream.continually {
  val ix = math.min(ptr+80,in.length)
  val ret = in.substring(ptr, ix)
  ptr = ix
  ret
}

out: scala.collection.immutable.Stream[String] = Stream(Unmentionable has an enthusiastic 35% of the popular vote. I discount the other 10% or s, ?)

但是块中take的语法是什么？我试过了：

val chunks = out.takeWhile( ptr < in.length)


<console>:13: error: type mismatch;
 found   : Boolean
 required: String => Boolean
           val ret = out.takeWhile( ptr < in.length)

Answer 1

以80个字符的块读取文件？怎么回事？

val in = io.Source.fromFile("file.txt").mkString.grouped(80)
while (in.hasNext) {
  // in.next is your chunk
}

Answer 2

你想要完成什么？如果您只是想将字符串（文件）分成块，则可以使用.grouped()或.groupBy()函数。

对于您当前的错误，编译器会告诉您需要执行的操作。你给了一个布尔：

val chunks = out.takeWhile(ptr < in.length) // ptr < in.length evaluates to a boolean

但你需要给一个带String的函数并返回一个布尔值：

val chunks = out.takeWhile(s => ptr < s.length)  // Something like this

TakeWhile会导致类型不匹配

2 个答案: