使用 Scala 的可变参数
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Using varargs from Scala
提问by oxbow_lakes
I'm tearing my hair out trying to figure out how to do the following:
我正在努力弄清楚如何执行以下操作：
def foo(msf: String, o: Any, os: Any*) = {
println( String.format(msf, o :: List(os:_*)) )
}
There's a reason why I have to declare the method with an oand an osSeqseparately. Basically, I end up with the format method called with a single object parameter (of type List). Attempting:
我必须用 ano和 anosSeq分别声明方法是有原因的。基本上，我最终得到了使用单个对象参数（类型为List）调用的格式方法。尝试：
def foo(msf: String, o: Any, os: Any*) = {
println( String.format(msf, (o :: List(os:_*))).toArray )
}
Gives me the type error:
给我类型错误：
found: Array[Any]
required Seq[java.lang.Object]
找到：数组[任何]
必需的序列[java.lang.Object]
I've tried casting, which compiles but fails for pretty much the same reason as the first example. When I try
我试过强制转换，它编译但失败的原因与第一个示例几乎相同。当我尝试
println(String.format(msg, (o :: List(os:_*)) :_* ))
this fails to compile with implicit conversion ambiguity (any2ArrowAssocand any2stringadd)
这无法编译隐式转换歧义（any2ArrowAssoc和any2stringadd）
回答by James Iry
def foo(msf: String, o: AnyRef, os: AnyRef*) =
println( String.format(msf, (o :: os.toList).toArray : _* ))
回答by Daniel C. Sobral
def foo(msf: String, o: AnyRef, os: AnyRef*) =
println( String.format(msf, o :: os.toList : _* ) )
or
或者
def foo(msf: String, o: AnyRef, os: AnyRef*) =
println( msf format (o :: os.toList : _* ) )
I much prefer the latter, though it has no locale* support.
我更喜欢后者，尽管它没有语言环境* 支持。
- Scala 2.8 does have locale support with RichString's format.
- Scala 2.8 确实支持 RichString 格式的区域设置。
