在Pyspark中解析JSON文件

Question

我对Pyspark很新.我尝试使用以下代码解析JSON文件

from pyspark.sql import SQLContext
sqlContext = SQLContext(sc)
df = sqlContext.read.json("file:///home/malwarehunter/Downloads/122116-path.json")
df.printSchema()

输出如下.

root | - _corrupt_record:string(nullable = true)

df.show()

输出看起来像这样

+--------------------+
|     _corrupt_record|
+--------------------+
|                   {|
|  "time1":"2...|
|  "time2":"201...|
|    "step":0.5,|
|          "xyz":[|
|                   {|
|      "student":"00010...|
|      "attr...|
|        [ -2.52, ...|
|        [ -2.3, -...|
|        [ -1.97, ...|
|        [ -1.27, ...|
|        [ -1.03, ...|
|        [ -0.8, -...|
|        [ -0.13, ...|
|        [ 0.09, -...|
|        [ 0.54, -...|
|        [  1.1, -...|
|        [ 1.34, 0...|
|        [ 1.64, 0...|
+--------------------+
only showing top 20 rows

Json文件看起来像这样.

{
  "time1":"2016-12-16T00:00:00.000",

  "time2":"2016-12-16T23:59:59.000",

  "step":0.5,

   "xyz":[

    {
     "student":"0001025D0007F5DB",
      "attr":[
    [ -2.52, -1.17 ],
    [ -2.3, -1.15 ],
    [ -1.97, -1.19 ],
    [ 10.16, 4.08 ],
    [ 10.23, 4.87 ],
    [ 9.96, 5.09 ] ]
},
{
  "student":"0001025D0007F5DC",
  "attr":[
    [ -2.58, -0.99 ],
    [ 10.12, 3.89 ],
    [ 10.27, 4.59 ],
    [ 10.05, 5.02 ] ]
}
]}

你能帮我解析一下并创建这样的数据框吗？

Answer 1

Spark> = 2.2:

您可以使用multiLineJSON阅读器的参数:

spark.read.json(path_to_input, multiLine=True)

Spark <2.2

几乎是通用但相当昂贵的解决方案,可用于读取多行JSON文件:

• 使用读取数据SparkContex.wholeTextFiles.
• 删除密钥(文件名).
• 将结果传递给DataFrameReader.json.

只要您的数据没有其他问题,它应该可以解决问题:

spark.read.json(sc.wholeTextFiles(path_to_input).values())