Check out example codes for "pyspark dense". It will help you in understanding the concepts better.

Code Example 1

import pyspark.sql.functions as F
import pyspark.sql.types as T

#or: to_array = F.udf(lambda v: list([float(x) for x in v]), T.ArrayType(T.FloatType()))
to_array = F.udf(lambda v: v.toArray().tolist(), T.ArrayType(T.FloatType()))
df = df.withColumn('features', to_array('features'))

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