[英]How to convert an RDD of Maps to dataframe
I have RDD of Map and i want to converted it to dataframe Here is the input format of RDD 我有地图的RDD,我想将其转换为数据帧这是RDD的输入格式
val mapRDD: RDD[Map[String, String]] = sc.parallelize(Seq(
Map("empid" -> "12", "empName" -> "Rohan", "depId" -> "201"),
Map("empid" -> "13", "empName" -> "Ross", "depId" -> "201"),
Map("empid" -> "14", "empName" -> "Richard", "depId" -> "401"),
Map("empid" -> "15", "empName" -> "Michale", "depId" -> "501"),
Map("empid" -> "16", "empName" -> "John", "depId" -> "701")))
is there any way to convert into dataframe like 有没有办法转换成数据帧,如
val df=mapRDD.toDf
df.show df.show
empid, empName, depId
12 Rohan 201
13 Ross 201
14 Richard 401
15 Michale 501
16 John 701
You can easily convert it into Spark DataFrame: 您可以轻松将其转换为Spark DataFrame:
Here is a code that would do the trick : 这是一个可以解决问题的代码:
val mapRDD= sc.parallelize(Seq(
Map("empid" -> "12", "empName" -> "Rohan", "depId" -> "201"),
Map("empid" -> "13", "empName" -> "Ross", "depId" -> "201"),
Map("empid" -> "14", "empName" -> "Richard", "depId" -> "401"),
Map("empid" -> "15", "empName" -> "Michale", "depId" -> "501"),
Map("empid" -> "16", "empName" -> "John", "depId" -> "701")))
val columns=mapRDD.take(1).flatMap(a=>a.keys)
val resultantDF=mapRDD.map{value=>
val list=value.values.toList
(list(0),list(1),list(2))
}.toDF(columns:_*)
resultantDF.show()
The output is : 输出是:
+-----+-------+-----+
|empid|empName|depId|
+-----+-------+-----+
| 12| Rohan| 201|
| 13| Ross| 201|
| 14|Richard| 401|
| 15|Michale| 501|
| 16| John| 701|
+-----+-------+-----+
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