Question

I have a list of tuples that look like this.

[ [(1,True),(2,True)] , [(3,False),(4,False),(5,False)] ]

My goal is so get [1,2,3,4,5] of out that mess.

I tried to use map and filter to remove all the Bools but filter also removed the first element in the tuple. If I can remove the Bools in each tuple then I can maybe use a loop to assign fst of each tuple to a new empty list?

Answer 1

f :: [[(a, b)]] -> [a]
f = concatMap (map fst)

Then f [ [(1,True),(2,True)] , [(3,False),(4,False),(5,False)] ] is [1,2,3,4,5].