Add double quotes to the StringType columns

[#1]

Hi All,

I am trying to add double quotes around the column type that are of string type in spark dataframe, how can I do that

for eg

Initial DF

col1    |   col2    | col3

1        |    abc     | px01

After adding the quotes to the alphanumeric data ie to the string type columns the final dataframe should be

col1    |   col2       |  col3

1        |    "abc"     | "px01"