python - how to use a variable in selenium webdriver find element by xpath? -

So I have a variable named folder containing a string that I randomly generate. I want to use xpath to search for this folder by name, and I'm not sure how to implement it

  driver.find_element_by_xpath ('// div [text () = 'Variable'] ')   
 Where the variable contains random text, it will happen with SQL (* select * from the table where the value = (?)), [Variable] ... or Something similar   
 
 
 try this:  
  driver.find_element_by_xpath ( '// div [text () ='% s ']'% variable)