kll_sketch_merge_double

Merges two KLL double sketch buffers together into one.

Syntax

from pyspark.sql import functions as sf

sf.kll_sketch_merge_double(left, right)

Parameters

Parameter Type Description
left pyspark.sql.Column or str The first KLL double sketch.
right pyspark.sql.Column or str The second KLL double sketch.

Returns

pyspark.sql.Column: The merged KLL sketch.

Examples

Example 1: Merge two KLL double sketches

from pyspark.sql import functions as sf
df = spark.createDataFrame([1.0,2.0,3.0,4.0,5.0], "DOUBLE")
sketch_df = df.agg(sf.kll_sketch_agg_double("value").alias("sketch"))
result = sketch_df.select(sf.kll_sketch_merge_double("sketch", "sketch")).first()[0]
result is not None and len(result) > 0
True