Reading Lines from Sample Code in 'Programming in Scala'
Working through a sample in Chapter 3 of "Programming in Scala", the following code doesn't seem working on Scala 2.8:
import scala.io.Source
if (args.length > 开发者_如何学编程0) {
for (line <- Source.fromFile(args(0)).getLines)
print(line.length + " " + line)
}
else
Console.err.println("Filename required.")
Scala complains fromFile
is expecting type java.io.File
. With a bit of searching it seems that I should be using fromPath
instead...
for (line <- Source.fromPath(args(0)).getLines)
However, I now get a puzzling error from that (puzzling to a beginner anyways):
... :4: error: missing arguments for method getLines in class Source;
follow this method with `_' if you want to treat it as a partially applied function
Error occurred in an application involving default arguments.
for (line <- Source.fromPath(args(0)).getLines)
^
one error found
I took a guess at trying...
for (line <- Source.fromPath(args(0)).getLines _)
And that didn't work. What's the Scala 2.8 way of making getLines
work?
The signature of getLines is this:
def getLines(separator: String = compat.Platform.EOL): Iterator[String] = new LineIterator(separator)
So it has a default argument. You need to write getLines()
instead, so that this default will be used.
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