Union of multiple sets in python

Question

[[1, \'34\', \'44\'], [1, \'40\', \'30\', \'41\'], [1, \'41\', \'40\', \'42\'], [1, \'42\', \'41\', \'43\'], [1, \'43\', \'42\', \'44\'], [1, \'44\', \'34\', \'43\']         


        

Answer 1

Tested with python 2 only: I personally like the readability of reduce, paired with a simple conditional function, something like

somelists = [[1, '41', '40', '42'], [1, '42', '41', '43'], [1, '43', '42', '44'], [1, '44', '34', '43']] # your original lists
somesets = map(set,somelists) #your lists as sets

def condition(s1,s2): # condition to apply recursively to the sets
    if s1.intersection(s2):
        return s1.union(s2)
reduce( condition,somesets)
#{1, '30', '34', '40', '41', '42', '43', '44'}

Of course you can cast this result to a 2d list if you desire list([reduce(...

I will note that this is something like 3x slower than the chain.fromiterable answer.