Spark 数据框中结构体的字段名称列表

Question

我有一个具有以下架构的数据框：

root
 |-- _id: long (nullable = true)
 |-- student_info: struct (nullable = true)
 |    |-- firstname: string (nullable = true)
 |    |-- lastname: string (nullable = true)
 |    |-- major: string (nullable = true)
 |    |-- hounour_roll: boolean (nullable = true)
 |-- school_name: string (nullable = true)

如何仅获取“student_info”下的列列表？IE["firstname","lastname","major","honour_roll"]

Answer 1

以下所有内容都返回结构体的字段名称列表。该.columns方法看起来最干净。

df.select("student_info.*").columns

df.schema["student_info"].dataType.names

df.schema["student_info"].dataType.fieldNames()

df.select("student_info.*").schema.names

df.select("student_info.*").schema.fieldNames()