<p>我做了一些简单的测量,以下是我的结果:</p>
<pre><code>import timeit
from itertools import chain
a = [*range(1, 10)]
b = [*range(1, 10)]
c = [*range(1, 10)]
tests = ("""output = list(chain(a, b, c))""",
"""output = a + b + c""",
"""output = [*chain(a, b, c)]""",
"""output = a.copy();output.extend(b);output.extend(c);""",
"""output = [*a, *b, *c]""",
"""output = a.copy();output+=b;output+=c;""",
"""output = a.copy();output+=[*b, *c]""",
"""output = a.copy();output += b + c""")
results = sorted((timeit.timeit(stmt=test, number=1, globals=globals()), test) for test in tests)
for i, (t, stmt) in enumerate(results, 1):
print(f'{i}.\t{t}\t{stmt}')
</code></pre>
<p>在我的机器上打印(AMD 2400G,Python 3.6.7):</p>
<pre><code>1. 6.010000106471125e-07 output = [*a, *b, *c]
2. 7.109999842214165e-07 output = a.copy();output += b + c
3. 7.720000212430023e-07 output = a.copy();output+=b;output+=c;
4. 7.820001428626711e-07 output = a + b + c
5. 1.0520000159885967e-06 output = a.copy();output+=[*b, *c]
6. 1.4030001693754457e-06 output = a.copy();output.extend(b);output.extend(c);
7. 1.4820000160398195e-06 output = [*chain(a, b, c)]
8. 2.525000127207022e-06 output = list(chain(a, b, c))
</code></pre>