scala 如何在Scala中将字符串列表打印为标准错误？
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How to print a list of strings to standard error in Scala?
提问by ektrules
This line causes a compile error:
此行导致编译错误：
astgen.typeError.foreach(System.err.println)
typeError is a scala.collection.immutable.List of Strings in the object astgen.
typeError 是对象 astgen 中的 scala.collection.immutable.List 字符串。
The error I'm getting is:
我得到的错误是：
error: ambiguous reference to overloaded definition,
both method println in class PrintStream of type (java.lang.String)Unit
and method println in class PrintStream of type (Array[Char])Unit
match expected type (Nothing) => Unit
astgen.typeError.foreach(System.err.println)
I'm new to Scala and don't understand the problem. Using 2.7.7final.
我是 Scala 的新手，不明白这个问题。使用 2.7.7final。
回答by pedrofurla
Even not being able to exactly reproduce the problem, I do know you can solve the ambiguity by specifying the type:
即使无法准确重现问题，我也知道您可以通过指定类型来解决歧义：
scala> List("a","b","c")
res0: List[java.lang.String] = List(a, b, c)
scala> res0.foreach(System.err.println(_:String))
a
b
c
In this example the _:Stringis unnecessary, it maybe necessary in your use case.
在这个例子中_:String是不必要的，在你的用例中可能是必要的。
回答by Benoit
According to RosettaCode, calling the built-in ConsoleAPI is better than calling the Java runtime library with System.err:
根据RosettaCode，调用内置ConsoleAPI 比调用 Java 运行时库更好System.err：
scala> List("aa", "bb", "cc").foreach(Console.err.println(_))
aa
bb
cc
