[Python]反转列表list的四种方法及性能

def r1(l):
    return l.reverse()

def r2(l):
    return l[::-1]


def r3(l):
    return list(reversed(l))

def r4(l):
    return sorted(l,reverse=True)

import time 

l = ['1','2','3','4']

s=time.time()
for i in range(0,10000000):
    r1(l)
e = time.time()
print(str(e-s))

s=time.time()
for i in range(0,10000000):
    r2(l)
e = time.time()
print(str(e-s))

s=time.time()
for i in range(0,10000000):
    r3(l)
e = time.time()
print(str(e-s))

s=time.time()
for i in range(0,10000000):
    r4(l)
e = time.time()
print(str(e-s))

分别循环10w，100w，1000w次，时间差不多，直接调用列表的reverse()函数更快

输出

0.0189821720123291
0.02794337272644043
0.05896449089050293
0.05294609069824219

0.20182347297668457
0.3256387710571289
0.5704410076141357
0.5014650821685791

2.002959728240967
2.8410980701446533
5.912968158721924
5.090804576873779