我正在使用 pyspark 创建一个数据框,如下所示:
+----+------+
| k| v|
+----+------+
|key1|value1|
|key1|value1|
|key1|value1|
|key2|value1|
|key2|value1|
|key2|value1|
+----+------+
我想使用“withColumn”方法添加一个“rowNum”列,数据框的结果更改如下:
+----+------+------+
| k| v|rowNum|
+----+------+------+
|key1|value1| 1|
|key1|value1| 2|
|key1|value1| 3|
|key2|value1| 4|
|key2|value1| 5|
|key2|value1| 6|
+----+------+------+
rowNum的范围是从1到n,n等于raws的数量。我修改了我的代码,如下所示:
from pyspark.sql.window import Window
from pyspark.sql import functions as F
w = Window().partitionBy("v").orderBy('k')
my_df= my_df.withColumn("rowNum", F.rowNumber().over(w))
但是,我收到错误消息:
'module' object has no attribute 'rowNumber'
我将rowNumber()方法替换为row_number,上面的代码可以运行。但是,当我运行代码时:
my_df.show()
我再次收到错误消息:
Py4JJavaError: An error occurred while calling o898.showString.
: java.lang.UnsupportedOperationException: Cannot evaluate expression: row_number()
at org.apache.spark.sql.catalyst.expressions.Unevaluable$class.doGenCode(Expression.scala:224)
at org.apache.spark.sql.catalyst.expressions.aggregate.DeclarativeAggregate.doGenCode(interfaces.scala:342)
at org.apache.spark.sql.catalyst.expressions.Expression$$anonfun$genCode$2.apply(Expression.scala:104)
at org.apache.spark.sql.catalyst.expressions.Expression$$anonfun$genCode$2.apply(Expression.scala:101)
at scala.Option.getOrElse(Option.scala:121)
最佳答案
Spark 2.2中的解决方案:
from pyspark.sql.functions import row_number,lit
from pyspark.sql.window import Window
w = Window().orderBy(lit('A'))
df = df.withColumn("rowNum", row_number().over(w))
关于pyspark - 在数据框中添加一列,其中包含从 1 到 n 的值,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42690565/