如何将字典列表转换为Pyspark DataFrame

我想将我的词典列表转换为DataFrame.这是清单：

mylist = 
[
  {"type_activity_id":1,"type_activity_name":"xxx"},
  {"type_activity_id":2,"type_activity_name":"yyy"},
  {"type_activity_id":3,"type_activity_name":"zzz"}
]

这是我的代码：

from pyspark.sql.types import StringType

df = spark.createDataFrame(mylist, StringType())

df.show(2,False)

+-----------------------------------------+
|                                    value|
+-----------------------------------------+
|{type_activity_id=1,type_activity_id=xxx}|
|{type_activity_id=2,type_activity_id=yyy}|
|{type_activity_id=3,type_activity_id=zzz}|
+-----------------------------------------+

我假设我应该为每列提供一些映射和类型,但我不知道该怎么做.

更新：

我也试过这个：

schema = ArrayType(
    StructType([StructField("type_activity_id", IntegerType()),
                StructField("type_activity_name", StringType())
                ]))
df = spark.createDataFrame(mylist, StringType())
df = df.withColumn("value", from_json(df.value, schema))

但后来我得到空值：

+-----+
|value|
+-----+
| null|
| null|
+-----+

解决方法:

你可以这样做.您将获得一个包含2列的数据框.

mylist = [
  {"type_activity_id":1,"type_activity_name":"xxx"},
  {"type_activity_id":2,"type_activity_name":"yyy"},
  {"type_activity_id":3,"type_activity_name":"zzz"}
]

myJson = sc.parallelize(mylist)
myDf = sqlContext.read.json(myJson)

输出：

+----------------+------------------+
|type_activity_id|type_activity_name|
+----------------+------------------+
|               1|               xxx|
|               2|               yyy|
|               3|               zzz|
+----------------+------------------+

标签：python,pyspark,apache-spark-sql
来源： https://codeday.me/bug/20191008/1870847.html