将List [String]传递给采用f(args:String *)标量的函数 [英] Pass List[String] to function that takes f(args: String*) scala

问题描述

我需要用spark读取特定的实木复合地板文件，我知道可以这样做:

I need to read in specific parquet files with spark, I know this can be done like so:

sqlContext
    .read
    .parquet("s3://bucket/key", "s3://bucket/key")

现在我有一个List [String]对象，其中包含所有这些s3路径，但是我不知道如何将其以编程方式传递给Scala中的镶木地板函数?有很多文件可以手动执行，有什么想法如何以编程方式将文件添加到镶木地板功能中?

Right now I have a List[String] object with all these s3 paths in it but I don't know how I can pass this programmatically to the parquet function in Scala? There are way to many files to do it manually, any ideas how to get the files into the parquet function programmatically?

推荐答案

我早些时候已经回答了有关重复参数的类似问题此处.

I've answer a similar question earlier concerning repeated parameters here.

如@Dima所述，您正在寻找一个splat运算符，因为 .parquet 期望重复的参数:

As @Dima mentioned, you are looking for a splat operator because .parquet expected repeated arguments :

sqlContext.read.parquet(listOfStrings:_*)

Scala语言规范 4.6中的重复自变量的更多信息.2

More on repeated arguments in the Scala Language Specification seciton 4.6.2

尽管这是scala 2.9的规格，但此部分没有更改.

Although it's the specs of scala 2.9, this part didn't change.

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