填空题 请根据下列scala代码给出对应的代码解释 val data = Array(20,40,60,80,100); ① val rdd = sc.parallelize(data); ② val rdd2 = rdd.map(x=>x+10); ③ val rdd3 = rdd2.filter(x=> x>50); ④ val stu_df = spark.read.json("file:///home/hadoop/student.json"); ⑤ stu_df.select(df("name"),df("age")).show();