Converting list of tuples into a dictionary

Question

I\'m looking for a way to convert a list of tuples like this:

[(1,4),(2,4),(3,4),(4,15),(5,15),(6,23),(7,23),(8,23),(9,15),(10,23),(11,15),(12,15)]


        

Answer 1

l = [(1,4),(2,4),(3,4),(4,15),(5,15),(6,23),(7,23),(8,23),(9,15),(10,23),(11,15),(12,15)]
d = {}
for v, k in l:
    d.setdefault(k, []).append(v)