从 CSV 文件中拆分 JSON 值并根据 Spark/Scala 中的 json 键创建新列 [英] Split JSON value from CSV file and create new column based on json key in Spark/Scala

问题描述

CSV 文件中的数据如下所示.想要从 Desc 列中拆分 JSON 并使用键创建一个新列.在 Scala 中使用 spark 2.

Have data in CSV file below is the format. Want to split JSON from Desc column and create a new column with key.Using spark 2 with Scala.

+------+------------+----------------------------------+
|  id  |  Category  |           Desc                   |
+------+------------+----------------------------------+
|  201 |  MIS20     | { "Total": 200,"Defective": 21 } |
+------+-----------------------------------------------+
|  202 |  MIS30     | { "Total": 740,"Defective": 58 } |
+------+-----------------------------------------------+

输出:

So the desired output would be:

+------+------------+---------+-------------+
|  id  |  Category  |  Total  |  Defective  |
+------+------------+---------+-------------+
|  201 |  MIS20     |  200    |   21        |
+------+----------------------+-------------+
|  202 |  MIS30     |  740    |   58        | 
+------+------------------------------------+

非常感谢任何帮助.

推荐答案

为您的内部 json 创建一个 schema 并使用 from_json 应用该模式> 功能如下

Create a schema for your inner json and apply that schema with from_json function as below

val schema = new StructType()
  .add(StructField("Total", LongType, false)).
  add("Defective", LongType, false)

d.select($"id",$"Category", from_json($"Desc", schema).as("desc"))
  .select($"id",$"Category", $"desc.*")
  .show(false)

输出:

+---+--------+-----+---------+
|id |Category|Total|Defective|
+---+--------+-----+---------+
|201|MIS20   |200  |21       |
|202|MIS30   |740  |58       |
+---+--------+-----+---------+

希望这会有所帮助！

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