comparison.py

import random
import timeit

t1 = [[random.randint(-100, 100), 0] for n in range(10000)]
t2 = [[random.randint(-100, 100), 0] for n in range(10000)]

print('{:^24} | {:^24}'.format('Dict unpacking', 'List concat'))
for i in range(10):
  s1 = timeit.timeit('d = {**dict(t1), **dict(t2)}', number=1000, globals= globals())
  s2 = timeit.timeit('d = dict(t1 + t2)', number=1000, globals= globals())
  print('{:>20} [s] | {:<20} [s]'.format(s1, s2))

"""
     Dict unpacking      |    List concat
  0.8616442901628716 [s] | 0.8781542848391837   [s]
  0.8472575716691608 [s] | 0.8787916687937241   [s]
   0.848999438460396 [s] | 0.8818265353004335   [s]
  0.8478398955683133 [s] | 0.8879287209293807   [s]
  0.8516667517484393 [s] | 0.8954026676778994   [s]
  0.8610772809813625 [s] | 0.9234632410317545   [s]
  0.8664917628698277 [s] | 0.917044915878364    [s]
  0.8672644268284557 [s] | 0.8892964710515798   [s]
  0.8557634386645532 [s] | 0.8915499223325014   [s]
  0.8565915273148903 [s] | 0.8864756459529417   [s]
"""

print('{:^24} | {:^24}'.format('Dict unpacking', 'Dict updating'))
for i in range(10):
  s1 = timeit.timeit('d = {**dict(t1), **dict(t2)}', number=1000, globals= globals())
  s2 = timeit.timeit('d = dict(t1); d.update(t2)', number=1000, globals= globals())
  print('{:>20} [s] | {:<20} [s]'.format(s1, s2))

"""
     Dict unpacking      |    Dict updating
  0.8729662419871147 [s] | 0.834746906062378    [s]
  0.8501013688440935 [s] | 0.8382886167893275   [s]
   0.847772073248052 [s] | 0.8357704396782992   [s]
  0.8622331775121665 [s] | 0.8696393019406514   [s]
  0.8678635239893993 [s] | 0.8817649117944484   [s]
  0.8997013630098536 [s] | 0.8684148538173986   [s]
  0.8556343574746279 [s] | 0.8308821277247489   [s]
  0.9734169322433672 [s] | 0.8827789648710223   [s]
   0.848005805007233 [s] | 0.8577842520949162   [s]
  0.8728422657030706 [s] | 0.8670835673081001   [s]
"""