How can I get the column data based on specific column name and then stored these data in array or list ?

[zml张明磊]

Hi,

       I am a new to Scala and Spark and trying to find relative API in 
DataFrame to solve my problem as title described. However, I just only find 
this API DataFrame.col(colName : String) : Column which returns an object of 
Column. Not the content. If only DataFrame support such API which like 
Column.toArray : Type is enough for me. But now, it doesn’t. How can I do can 
achieve this function ?

Thanks,
Minglei.