machine-learning - 如何在 azure databricks 中导出我的预测（数组）？

Question

我无法将我的数据框导出到 csv。消息“CSV 数据源不支持数组”

predictions.write.option("delimiter", "\t").csv("/mnt/classification2018/testpredic2")

我尝试了这个命令但连接了，但没有成功

from pyspark.sql.functions import concat_ws

predictions.withColumn("probability", concat_ws(",", "probability")).show()

日志错误

/databricks/spark/python/pyspark/sql/utils.py in deco(*a, **kw)
     61     def deco(*a, **kw):
     62         try:
---> 63             return f(*a, **kw)
     64         except py4j.protocol.Py4JJavaError as e:
     65             s = e.java_exception.toString()

/databricks/spark/python/lib/py4j-0.10.7-src.zip/py4j/protocol.py in get_return_value(answer, gateway_client, target_id, name)
    326                 raise Py4JJavaError(
    327                     "An error occurred while calling {0}{1}{2}.\n".
--> 328                     format(target_id, ".", name), value)
    329             else:
    330                 raise Py4JError(

Py4JJavaError: An error occurred while calling o1472.csv.
: java.lang.UnsupportedOperationException: CSV data source does not support array<string> data type.
    at org.apache.spark.sql.execution.datasources.csv.CSVUtils$.org$apache$spark$sql$execution$datasources$csv$CSVUtils$$verifyType$1(CSVUtils.scala:127) 

Answer 1

将列转换为字符串并写入 csv

from pyspark.sql.functions import col
predictions = predictions.withColumn("probability", col("probability").cast("string))
predictions.write.option("delimiter", "\t").csv("/mnt/classification2018/testpredic2")