diff --git a/strings.py b/strings.py
index dea9c43..2622f56 100644
--- a/strings.py
+++ b/strings.py
@@ -5,7 +5,7 @@ from pyspark.sql.types import StringType, ArrayType, StructType, StructField, Do
 from affro_cluster import *
 
 from pyspark.sql import SparkSession
-from pyspark.sql.functions import col, explode, first, collect_list, udf
+from pyspark.sql.functions import col, explode, first, collect_set, udf
 import sys
 
 spark = SparkSession.builder.appName("JSONProcessing").getOrCreate()
@@ -81,7 +81,7 @@ affs.join(exploded, on="affiliation") \
             ) \
     .groupBy("DOI") \
     .agg(first("OAlex").alias("OAlex"), #for each DOI it says what are the other columns Since OALEX is equal for each doi just select the first, while use the collect_list function to aggregate the Matchings
-         collect_list("match").alias("Matchings") #each exploded match is collected again
+         collect_set("match").alias("Matchings") #each exploded match is collected again
          ) \
     .write \
     .mode("overwrite") \