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问题描述

我遇到这个错误:

。java.lang.ClassCastException:scala.collection.immutable $结肠结肠$不能转换为[Ljava.lang.Object;

每当我尝试使用包含找到一个字符串是否是一个数组里面。是否有这样做的更合适的方式?或者,我是不是做错了什么? (我是相当新的斯卡拉)

I am encountering this error:java.lang.ClassCastException: scala.collection.immutable.$colon$colon cannot be cast to [Ljava.lang.Object;whenever I try to use "contains" to find if a string is inside an array. Is there a more appropriate way of doing this? Or, am I doing something wrong? (I am fairly new to Scala)

下面是code:

val matches = Set[JSONObject]()
val config = new SparkConf()
val sc = new SparkContext("local", "SparkExample", config)
val sqlContext = new org.apache.spark.sql.SQLContext(sc)

val ebay = sqlContext.read.json("/Users/thomassquires/Downloads/products.json")
val catalogue = sqlContext.read.json("/Users/thomassquires/Documents/catalogue2.json")

val eins = ebay.map(item => (item.getAs[String]("ID"), Option(item.getAs[Set[Row]]("itemSpecifics"))))
  .filter(item => item._2.isDefined)
  .map(item => (item._1 , item._2.get.find(x => x.getAs[String]("k") == "EAN")))
  .filter(x => x._2.isDefined)
  .map(x => (x._1, x._2.get.getAs[String]("v")))
  .collect()

    def catEins =  catalogue.map(r => (r.getAs[String]("_id"), Option(r.getAs[Array[String]]("item_model_number")))).filter(r => r._2.isDefined).map(r => (r._1, r._2.get)).collect()

  def matched = for(ein <- eins) yield (ein._1, catEins.filter(z => z._2.contains(ein._2)))

在最后一行时,会出现异常。我已经尝试了一些不同的变种。

The exception occurs on the last line. I have tried a few different variants.

我的数据结构是列表[Tuple2 [字符串,字符串]] 和一个列表[Tuple2 [字符串,数组[字符串]]] 。我需要找到第二个列表包含字符串的零个或更多的匹配。

My data structure is one List[Tuple2[String, String]] and one List[Tuple2[String, Array[String]]] . I need to find the zero or more matches from the second list that contain the string.

感谢

推荐答案

长话短说(还有,在这里我摸不透*一部分)你用错误的类型。 getAs 实现为字段索引字符串=&GT;诠释 ),其次是 GET 智力=&GT;任何),其次是 asInstanceOf

Long story short (there is still part that eludes me here*) you're using wrong types. getAs is implemented as fieldIndex (String => Int) followed by get (Int => Any) followed by asInstanceOf.

由于星火不使用阵列也不设置,但 WrappedArray 存储阵列列数据,调用,例如 getAs [数组[字符串]] getAs [设置[行] 无效。如果你想具体的类型,您应该使用 getAs [SEQ [T] getAsSeq [T] 和转换您数据所需的类型与 toSet / 的toArray

Since Spark doesn't use Arrays nor Sets but WrappedArray to store array column data, calls like getAs[Array[String]] or getAs[Set[Row]] are not valid. If you want specific types you should use either getAs[Seq[T]] or getAsSeq[T] and convert your data to desired type with toSet / toArray.

*请参阅

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09-26 18:41