将 PySpark 数据框列从列表转换为字符串 [英] Convert PySpark dataframe column from list to string
本文介绍了将 PySpark 数据框列从列表转换为字符串的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有这个 PySpark 数据框
I have this PySpark dataframe
+-----------+--------------------+
|uuid | test_123 |
+-----------+--------------------+
| 1 |[test, test2, test3]|
| 2 |[test4, test, test6]|
| 3 |[test6, test9, t55o]|
我想将 test_123
列转换成这样:
and I want to convert the column test_123
to be like this:
+-----------+--------------------+
|uuid | test_123 |
+-----------+--------------------+
| 1 |"test,test2,test3" |
| 2 |"test4,test,test6" |
| 3 |"test6,test9,t55o" |
所以从列表变成字符串.
so from list to be string.
我怎样才能用 PySpark 做到这一点?
how can I do it with PySpark?
推荐答案
您可以创建一个 udf
加入 array/list 然后将其应用到 测试栏:
You can create a udf
that joins array/list and then apply it to the test column:
from pyspark.sql.functions import udf, col
join_udf = udf(lambda x: ",".join(x))
df.withColumn("test_123", join_udf(col("test_123"))).show()
+----+----------------+
|uuid| test_123|
+----+----------------+
| 1|test,test2,test3|
| 2|test4,test,test6|
| 3|test6,test9,t55o|
+----+----------------+
初始数据框创建自:
from pyspark.sql.types import StructType, StructField
schema = StructType([StructField("uuid",IntegerType(),True),StructField("test_123",ArrayType(StringType(),True),True)])
rdd = sc.parallelize([[1, ["test","test2","test3"]], [2, ["test4","test","test6"]],[3,["test6","test9","t55o"]]])
df = spark.createDataFrame(rdd, schema)
df.show()
+----+--------------------+
|uuid| test_123|
+----+--------------------+
| 1|[test, test2, test3]|
| 2|[test4, test, test6]|
| 3|[test6, test9, t55o]|
+----+--------------------+
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