How do I add sparse vectors after a group using Spark SQL?
I am using a news recommendation system and I need to create a spreadsheet for the users and the news they read. my original data:
001436800277225 ["9161492","9161787","9378531"]
009092130698762 ["9394697"]
010003000431538 ["9394697","9426473","9428530"]
010156461231357 ["9350394","9414181"]
010216216021063 ["9173862","9247870"]
010720006581483 ["9018786"]
011199797794333 ["9017977","9091134","9142852","9325464","9331913"]
011337201765123 ["9161294","9198693"]
011414545455156 ["9168185","9178348","9182782","9359776"]
011425002581540 ["9083446","9161294","9309432"]
and I am using spark-SQL do explode and one hot encoding,
df = getdf()
df1 = df.select('uuid',explode('news').alias('news'))
stringIndexer = StringIndexer(inputCol="news", outputCol="newsIndex")
model = stringIndexer.fit(df1)
indexed = model.transform(df1)
encoder = OneHotEncoder(inputCol="newsIndex", outputCol="newsVec")
encoded = encoder.transform(indexed)
encoded.show(20,False)
After that, my data becomes:
+---------------+-------+---------+----------------------+
|uuid |news |newsIndex|newsVec |
+---------------+-------+---------+----------------------+
|014324000386050|9398253|10415.0 |(105721,[10415],[1.0])|
|014324000386050|9428530|70.0 |(105721,[70],[1.0]) |
|014324000631752|654112 |1717.0 |(105721,[1717],[1.0]) |
|014324000674240|730531 |2282.0 |(105721,[2282],[1.0]) |
|014324000674240|694306 |1268.0 |(105721,[1268],[1.0]) |
|014324000674240|712016 |4766.0 |(105721,[4766],[1.0]) |
|014324000674240|672307 |7318.0 |(105721,[7318],[1.0]) |
|014324000674240|698073 |1241.0 |(105721,[1241],[1.0]) |
|014324000674240|728044 |5302.0 |(105721,[5302],[1.0]) |
|014324000674240|672256 |1619.0 |(105721,[1619],[1.0]) |
|014324000674240|730236 |2376.0 |(105721,[2376],[1.0]) |
|014324000674240|730235 |14274.0 |(105721,[14274],[1.0])|
|014324000674240|728509 |1743.0 |(105721,[1743],[1.0]) |
|014324000674240|704528 |10310.0 |(105721,[10310],[1.0])|
|014324000715399|774134 |8876.0 |(105721,[8876],[1.0]) |
|014324000725836|9357431|3479.0 |(105721,[3479],[1.0]) |
|014324000725836|9358028|15621.0 |(105721,[15621],[1.0])|
|014324000730349|812106 |4599.0 |(105721,[4599],[1.0]) |
|014324000730349|699237 |754.0 |(105721,[754],[1.0]) |
|014324000730349|748109 |4854.0 |(105721,[4854],[1.0]) |
+---------------+-------+---------+----------------------+
But one id has multiple lines, so I want groupBy('uuid')
and then add
these vectors. But just use groupBy and then add an error. How can i do this?
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Starting with indexed
, we can collect the column newsIndex
as a list and convert it to SparseVector
using udf
.
To declare a sparse vector, we need a number of functions and a list of tuples containing position and value. Since we are dealing with a categorical variable, we will use for the value 1.0
. And the index will be the column newsIndex
:
from pyspark.sql.functions import collect_list, max, lit
from pyspark.ml.linalg import Vectors, VectorUDT
def encode(arr, length):
vec_args = length, [(x,1.0) for x in arr]
return Vectors.sparse(*vec_args)
encode_udf = udf(encode, VectorUDT())
Number of functions max(newsIndex) + 1
(since it StrinIndexer
starts with 0.0
):
feats = indexed.agg(max(indexed["newsIndex"])).take(1)[0][0] + 1
Putting it all together:
indexed.groupBy("uuid") \
.agg(collect_list("newsIndex")
.alias("newsArr")) \
.select("uuid",
encode_udf("newsArr", lit(feats))
.alias("OHE")) \
.show(truncate = False)
+---------------+-----------------------------------------+
|uuid |OHE |
+---------------+-----------------------------------------+
|009092130698762|(24,[0],[1.0]) |
|010003000431538|(24,[0,3,15],[1.0,1.0,1.0]) |
|010720006581483|(24,[11],[1.0]) |
|010216216021063|(24,[10,22],[1.0,1.0]) |
|001436800277225|(24,[2,12,23],[1.0,1.0,1.0]) |
|011425002581540|(24,[1,5,9],[1.0,1.0,1.0]) |
|010156461231357|(24,[13,18],[1.0,1.0]) |
|011199797794333|(24,[7,8,17,19,20],[1.0,1.0,1.0,1.0,1.0])|
|011414545455156|(24,[4,6,14,21],[1.0,1.0,1.0,1.0]) |
|011337201765123|(24,[1,16],[1.0,1.0]) |
+---------------+-----------------------------------------+
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