val df = Seq((2L, "a", "foo", 3.0)).toDF df.printSchema // root // |-- _1: long (nullable = false) // |-- _2: string (nullable = true) // |-- _3: string (nullable = true) // |-- _4: double (nullable = false)
最简单的办法toDF方法
val schemas= Seq("id", "x1", "x2", "x3")
val dfRenamed = df.toDF(schemas: _*)
dfRenamed.printSchema
// root
// |-- id: long (nullable = false)
// |-- x1: string (nullable = true)
// |-- x2: string (nullable = true)
// |-- x3: double (nullable = false)
如果要重命名单个列，可以使用以下任select一项alias：
df.select($"_1".alias("x1"))
可以很容易到多列：
val lookup = Map("_1" -> "foo", "_3" -> "bar")
df.select(df.columns.map(c => col(c).as(lookup.getOrElse(c, c))): _*)
或者withColumnRenamed：
df.withColumnRenamed("_1", "x1")
