[Python] How can I sum multiple columns in a spark dataframe in pyspark?

I've got a list of column names I want to sum

columns = ['col1','col2','col3']


How can I add the three and put it in a new column ? (in an automatic way, so that I can change the column list and have new results)

Dataframe with result I want:

col1 col2 col3 result
1 2 3 6

Continue reading...