美元符号在 Scala 中有什么作用 [英] What does dollar sign do in scala

问题描述

当我阅读 spark 源代码时 这里，我看到了像 $(a_variable) 这样的代码.什么意思?

When I was reading spark source code here, I saw code like $(a_variable). What does it mean?

我在这里复制代码:

  final val blockSize: IntParam = new IntParam(this, "blockSize",
    "Block size for stacking input data in matrices. Data is stacked within partitions." +
      " If block size is more than remaining data in a partition then " +
      "it is adjusted to the size of this data. Recommended size is between 10 and 1000",
    ParamValidators.gt(0))

  /** @group getParam */
  final def getBlockSize: Int = $(blockSize)

推荐答案

这不是特殊的 Scala 语法，它是一个方法名称.在 Scala 中 $ 是一个合法的标识符.该方法继承自 org.apache.spark.ml.param.Param trait.

That isn't special Scala syntax, it's a method name. In Scala $ is a legal identifier. The method is inherited from the org.apache.spark.ml.param.Param trait.

参见来源.

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