我有这样的数据:
1,Anna,London
2,Peter,Amsterdam
我想将这些数据作为数据帧加载到配置单元中,并添加引号,使数据帧中的数据看起来像这样:
"1" "Anna" "London"
"2" "Peter" "Amsterdam"
我已将分隔符设置为","。我知道存在引用函数,但它的作用恰恰相反。如何添加引号?
可以通过format_string
函数实现
scala> val df = Seq(("1","Anna","London"),("2","Peter","Amsterdam")).toDF()
df: org.apache.spark.sql.DataFrame = [_1: string, _2: string ... 1 more field]
scala> df.show()
+---+-----+---------+
| _1| _2| _3|
+---+-----+---------+
| 1| Anna| London|
| 2|Peter|Amsterdam|
+---+-----+---------+
scala> val c = df.columns.map(df(_)).map((format_string(""%s"",_)))
c: Array[org.apache.spark.sql.Column] = Array(format_string("%s", _1), format_string("%s", _2), format_string("%s", _3))
scala> df.select(c:_*).toDF(df.columns:_*).show()
+---+-------+-----------+
| _1| _2| _3|
+---+-------+-----------+
|"1"| "Anna"| "London"|
|"2"|"Peter"|"Amsterdam"|
+---+-------+-----------+