[SPARK-12480][FOLLOW-UP] use a single column vararg for hash

address comments in #10435

This makes the API easier to use if user programmatically generate the call to hash, and they will get analysis exception if the arguments of hash is empty.

Author: Wenchen Fan <wenchen@databricks.com>

Closes #10588 from cloud-fan/hash.

1 files changed, 12 insertions, 0 deletions

diff --git a/python/pyspark/sql/functions.py b/python/pyspark/sql/functions.py
index 7c15e38458..b0390cb994 100644
--- a/python/pyspark/sql/functions.py
+++ b/python/pyspark/sql/functions.py
@@ -1018,6 +1018,18 @@ def sha2(col, numBits):
     return Column(jc)
 
 
+@since(2.0)
+def hash(*cols):
+    """Calculates the hash code of given columns, and returns the result as a int column.
+
+    >>> sqlContext.createDataFrame([('ABC',)], ['a']).select(hash('a').alias('hash')).collect()
+    [Row(hash=1358996357)]
+    """
+    sc = SparkContext._active_spark_context
+    jc = sc._jvm.functions.hash(_to_seq(sc, cols, _to_java_column))
+    return Column(jc)
+
+
 # ---------------------- String/Binary functions ------------------------------
 
 _string_functions = {