使用 spark 读取 CSV 时，等同于 ^G 的分隔符是什么？

Question

所以，我真的需要帮助做一件愚蠢的事情，但显然我无法独自完成。

我在文件中有一组采用这种格式的行（在 OSX 上用 less 读取）：

XXXXXXXX^GT^XXXXXXXX^G\N^G0^GDL^G\N^G2018-09-14 13:57:00.0^G2018-09-16 00:00:00.0^GCompleted^G\N^G\N^G1^G2018-09-16 21:41:02.267^G1^G2018-09-16 21:41:02.267^GXXXXXXX^G\N
YYYYYYYY^GS^XXXXXXXX^G\N^G0^GDL^G\N^G2018-08-29 00:00:00.0^G2018-08-29 23:00:00.0^GCompleted^G\N^G\N^G1^G2018-09-16 21:41:03.797^G1^G2018-09-16 21:41:03.81^GXXXXXXX^G\N

所以分隔符是 BEL 分隔符，我以这种方式加载 CSV：

val df = sqlContext.read.format("csv")
  .option("header", "false")
  .option("inferSchema", "true")
  .option("delimiter", "\u2407")
  .option("nullValue", "\N")
  .load("part0000")

但是当我阅读它时，它只是以这种方式将行读取为一列：

XXXXXXXXCXXXXXXXX\N0DL\N2018-09-15 00:00:00.02018-09-16 00:00:00.0Completed\N\N12018-09-16 21:41:03.25712018-09-16 21:41:03.263XXXXXXXX\N
XXXXXXXXSXXXXXXXX\N0DL\N2018-09-15 00:00:00.02018-09-15 23:00:00.0Completed\N\N12018-09-16 21:41:03.3712018-09-16 21:41:03.373XXXXXXXX\N

似乎有一个 unkown character（你什么也看不到，因为我在 Whosebug 上对它进行了格式化）代替了 ^G。

更新：这可能是对 scala 的 spark 的限制吗？如果我运行以这种方式使用 scala 的代码：

val df = sqlContext.read.format("csv")
  .option("header", "false")
  .option("inferSchema", "true")
  .option("delimiter", "\a")
  .option("nullValue", "\N")
  .load("part-m-00000")

display(df)

我长胖了

java.lang.IllegalArgumentException: Unsupported special character for delimiter: \a

而如果我运行和 python:

df = sqlContext.read.format('csv').options(header='false', inferSchema='true', delimiter = "\a", nullValue = '\N').load('part-m-00000')

display(df)

一切都很好！

Answer 1

在 spark-scala 中这些版本看起来有限制，这是代码中支持的 csv 分隔符，

apache/spark/sql/catalyst/csv/CSVOptions.scala

val delimiter = CSVExprUtils.toChar(
    parameters.getOrElse("sep", parameters.getOrElse("delimiter", ",")))

--- CSVExprUtils.toChar

apache/spark/sql/catalyst/csv/CSVExprUtils.scala

  def toChar(str: String): Char = {
(str: Seq[Char]) match {
  case Seq() => throw new IllegalArgumentException("Delimiter cannot be empty string")
  case Seq('\') => throw new IllegalArgumentException("Single backslash is prohibited." +
    " It has special meaning as beginning of an escape sequence." +
    " To get the backslash character, pass a string with two backslashes as the delimiter.")
  case Seq(c) => c
  case Seq('\', 't') => '\t'
  case Seq('\', 'r') => '\r'
  case Seq('\', 'b') => '\b'
  case Seq('\', 'f') => '\f'
  // In case user changes quote char and uses \" as delimiter in options
  case Seq('\', '\"') => '\"'
  case Seq('\', '\'') => '\''
  case Seq('\', '\') => '\'
  case _ if str == """\u0000""" => '\u0000'
  case Seq('\', _) =>
    throw new IllegalArgumentException(s"Unsupported special character for delimiter: $str")
  case _ =>
    throw new IllegalArgumentException(s"Delimiter cannot be more than one character: $str")
}

使用 spark 读取 CSV 时，等同于 ^G 的分隔符是什么？

What's the delimiter equivalent of ^G when reading a CSV with spark?

scala

apache-spark

apache-spark-sql

azure-databricks