I am newbie in PySpark. I created spark dataframe,and I have a column "Countries" which contains list of countries. How can i groupBy my dataframe by single countries which exists in Country list
+-----------------+
| countries|
+-----------------+
| [Россия, Китай]|
| [Великобритания]|
| [Норвегия]|
| [Россия]|
| []|
| [США]|
| [Россия]|
| [США]|
| []|
| [Россия]|
| []|
| []|
| [Италия]|
| [Россия, Грузия]|
| [США]|
| []|
| []|
| []|
|[Великобритания ]|
| [Беларусь]|
+-----------------+