Merge nested list items based on a repeating value

Question

Although poorly written, this code:

marker_array = [[\'hard\',\'2\',\'soft\'],[\'heavy\',\'2\',\'light\'],[\'rock\',\'2\',\'feather\'],[\'fast\',\'3\'], [\'turtl         


        

Answer 1

from collections import defaultdict
d1 = defaultdict(list)
d2 = defaultdict(list)
for pxa in marker_array:
    d1[pxa[1]].extend(pxa[:1])
    d2[pxa[1]].extend(pxa[2:])

res = [[' '.join(d1[x]), x, ' '.join(d2[x])] for x in sorted(d1)]

If you really need 2-tuples (which I think is unlikely):

for p in res:
    if not p[-1]:
        p.pop()