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