SPRKPY1045

pyspark.sql.functions.map_values

Message: pyspark.sql.functions.map_values has a workaround

Category: Warning.

Description

This function is used to extract the list of values from a column that contains a map/dictionary (keys/values).

The issue appears when the tool detects the usage of pyspark.sql.functions.map_values which has a workaround.

Scenario

Input

Below is an example of the usage of the method map_values.

df = spark.createDataFrame(
    [(1, {'Apple': 'Fruit', 'Potato': 'Vegetable'})],
    ("id", "a_map"))

df.select(map_values("a_map")).show()

Output

The tool adds the EWI SPRKPY1045 indicating that a workaround can be implemented.

df = spark.createDataFrame(
    [(1, {'Apple': 'Fruit', 'Potato': 'Vegetable'})],
    ("id", "a_map"))
#EWI: SPRKPY1045 => pyspark.sql.functions.map_values has a workaround, see documentation for more info

df.select(map_values("a_map")).show()

Recommended fix

As a workaround, you can create an udf to get the values for a column. The below example shows how to create the udf, then assign it to F.map_values, and then make use of it.

from snowflake.snowpark import functions as F
from snowflake.snowpark.types import ArrayType, MapType

map_values_udf=None

def map_values(map):
    global map_values_udf
    if not map_values_udf:
        def _map_values(map: dict)->list:
            return list(map.values())
        map_values_udf = F.udf(_map_values,return_type=ArrayType(),input_types=[MapType()],name="map_values",is_permanent=False,replace=True)
    return map_values_udf(map)

F.map_values = map_values

df.select(map_values(colDict))

Additional recommendations

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