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array_union

Returns a new array containing the union of elements in col1 and col2, without duplicates.

Syntax

from pyspark.sql import functions as sf

sf.array_union(col1, col2)

Parameters

Parameter Type Description
col1 pyspark.sql.Column or str Name of column containing the first array.
col2 pyspark.sql.Column or str Name of column containing the second array.

Returns

pyspark.sql.Column: A new array containing the union of elements in col1 and col2.

Examples

Example 1: Basic usage

from pyspark.sql import Row, functions as sf
df = spark.createDataFrame([Row(c1=["b", "a", "c"], c2=["c", "d", "a", "f"])])
df.select(sf.sort_array(sf.array_union(df.c1, df.c2))).show()
+-------------------------------------+
|sort_array(array_union(c1, c2), true)|
+-------------------------------------+
|                      [a, b, c, d, f]|
+-------------------------------------+

Example 2: Union with no common elements

from pyspark.sql import Row, functions as sf
df = spark.createDataFrame([Row(c1=["b", "a", "c"], c2=["d", "e", "f"])])
df.select(sf.sort_array(sf.array_union(df.c1, df.c2))).show()
+-------------------------------------+
|sort_array(array_union(c1, c2), true)|
+-------------------------------------+
|                   [a, b, c, d, e, f]|
+-------------------------------------+

Example 3: Union with all common elements

from pyspark.sql import Row, functions as sf
df = spark.createDataFrame([Row(c1=["a", "b", "c"], c2=["a", "b", "c"])])
df.select(sf.sort_array(sf.array_union(df.c1, df.c2))).show()
+-------------------------------------+
|sort_array(array_union(c1, c2), true)|
+-------------------------------------+
|                            [a, b, c]|
+-------------------------------------+

Example 4: Union with null values

from pyspark.sql import Row, functions as sf
df = spark.createDataFrame([Row(c1=["a", "b", None], c2=["a", None, "c"])])
df.select(sf.sort_array(sf.array_union(df.c1, df.c2))).show()
+-------------------------------------+
|sort_array(array_union(c1, c2), true)|
+-------------------------------------+
|                      [NULL, a, b, c]|
+-------------------------------------+

Example 5: Union with empty arrays

from pyspark.sql import Row, functions as sf
from pyspark.sql.types import ArrayType, StringType, StructField, StructType
data = [Row(c1=[], c2=["a", "b", "c"])]
schema = StructType([
  StructField("c1", ArrayType(StringType()), True),
  StructField("c2", ArrayType(StringType()), True)
])
df = spark.createDataFrame(data, schema)
df.select(sf.sort_array(sf.array_union(df.c1, df.c2))).show()
+-------------------------------------+
|sort_array(array_union(c1, c2), true)|
+-------------------------------------+
|                            [a, b, c]|
+-------------------------------------+