Merge two dicts by same key [duplicate]

Answer 1

You could use extended iterable unpacking:

d1 = {
 'a': [2,4,5,6,8,10],
 'b': [1,2,5,6,9,12],
 'c': [0,4,5,8,10,21]
 }
d2 = {
 'a': [12,15],
 'b': [14,16],
 'c': [23,35]
  }

d_comb = {key:[*d1[key], *d2[key]] for key in d1}

print(d_comb)

Output

{'c': [0, 4, 5, 8, 10, 21, 23, 35], 'b': [1, 2, 5, 6, 9, 12, 14, 16], 'a': [2, 4, 5, 6, 8, 10, 12, 15]}