[oalex] fix python syntax errors

strings.py

@@ -22,21 +22,22 @@ def oalex_affro(doi, aff_string):
         return []
 
 
-spark.read.json(folder_path)
+spark.read.json(folder_path) \
-    .filter(col("doi").isNotNull())
+    .filter(col("doi").isNotNull()) \
     .select(
         col("doi").alias("DOI"),
         col("rors").alias("OAlex"),
         explode(col("raw_aff_string")).alias("aff_string") #this allows to split all the raw_aff_string and to parallelize better
-    )
+    ) \
-    .withColumn("Matchings", oalex_affro(col("doi"), col("aff_string"))) #this one says create a new column with name Matchinds as the result of the function as second argument
+    .drop(col("aff_string") #removes the aff_string column
-    .drop(col("aff_string")
+          )  \
-    .select(col("DOI"),col("OAlex"),explode("Matchins").alias("match")
+    .select(col("DOI"),col("OAlex"),explode("Matchins").alias("match")) \
-          .groupBy("DOI") #this groups by doi to have just one row per each doi
+    .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"))
+               collect_list("match").alias("Matchings") #each exploded match is collected again
-          .write
+               ) \
-          .mode("overwrite") #in case the folder already exists on hadoop it does not break
+          .write \
-          .option("compression","gzip") #to reduce the space
+          .mode("overwrite") \
+          .option("compression","gzip") \
           .json(hdfs_output_path)