list - print - schema spark

pyspark collect_set o collect_list con groupby

Question

¿Cómo puedo usar collect_set o collect_list en un marco de datos después de groupby ? por ejemplo: df.groupby(''key'').collect_set(''values'') . Me sale un error: AttributeError: ''GroupedData'' object has no attribute ''collect_set''

Answer 1

Necesitas usar agg. Ejemplo:

from pyspark import SparkContext
from pyspark.sql import HiveContext
from pyspark.sql import functions as F

sc = SparkContext("local")

sqlContext = HiveContext(sc)

df = sqlContext.createDataFrame([
    ("a", None, None),
    ("a", "code1", None),
    ("a", "code2", "name2"),
], ["id", "code", "name"])

df.show()

+---+-----+-----+
| id| code| name|
+---+-----+-----+
|  a| null| null|
|  a|code1| null|
|  a|code2|name2|
+---+-----+-----+

Tenga en cuenta que en lo anterior debe crear un HiveContext. Consulte https://.com/a/35529093/690430 para ver las diferentes versiones de Spark.

(df
  .groupby("id")
  .agg(F.collect_set("code"),
       F.collect_list("name"))
  .show())

+---+-----------------+------------------+
| id|collect_set(code)|collect_list(name)|
+---+-----------------+------------------+
|  a|   [code1, code2]|           [name2]|
+---+-----------------+------------------+