Python 字符串多替换时性能基准测试

结论

先说结果, 直接替换是最好的. replace 一层层用, 方法笨了一点, 还可以.

懒得打字, 贴代码就完事了.

基准测试1

from cProfile import run

s = '1 a  2 \n \t \r e34234'

def _replace():

    for x in range(5000000):

        old_value2 = s.replace('\t', '')

        old_value3 = old_value2.replace('\n', '')

        old_value3.replace('\r', '')

def _replace3():

    for x in range(5000000):

        old_value2 = s.replace('\t', '\\t')

        old_value3 = old_value2.replace('\n', '\\n')

        old_value3.replace('\r', '\\r')

def _translate1():

    for x in range(5000000):

        s.translate(str.maketrans({'\t': '', '\n': '', '\r': ''}))

t2 = str.maketrans({'\t': '', '\n': '', '\r': ''})

t3 = str.maketrans({'\t': None, '\n': None, '\r': None})

t4 = str.maketrans({'\t': '\\t', '\n': '\\n', '\r': '\\r'})

def _translate2():

    for x in range(5000000):

        s.translate(t2)

def _translate3():

    for x in range(5000000):

        s.translate(t3)

def _translate4():

    for x in range(5000000):

        s.translate(t4)

print('### replace')

run("_replace()")

print('### replace3')

run("_replace3()")

print('### translate1')

run("_translate1()")

print('### translate2')

run("_translate2()")

print('### translate3')

run("_translate3()")

print('### translate4')

run("_translate4()")

速度: _replace > translate3 > _replace3 > translate2 > translate1 > translate4

结论: translate是个辣鸡~~

运行结果:

### replace

         15000004 function calls in 4.451 seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)

        1    0.000    0.000    4.451    4.451 <string>:1(<module>)

        1    1.721    1.721    4.451    4.451 demo.py:7(_replace)

        1    0.000    0.000    4.451    4.451 {built-in method builtins.exec}

        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

 15000000    2.730    0.000    2.730    0.000 {method 'replace' of 'str' objects}

### replace3

         15000004 function calls in 4.785 seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)

        1    0.000    0.000    4.785    4.785 <string>:1(<module>)

        1    1.830    1.830    4.785    4.785 demo.py:14(_replace3)

        1    0.000    0.000    4.785    4.785 {built-in method builtins.exec}

        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

 15000000    2.956    0.000    2.956    0.000 {method 'replace' of 'str' objects}

### translate1

         10000004 function calls in 7.741 seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)

        1    0.000    0.000    7.741    7.741 <string>:1(<module>)

        1    1.870    1.870    7.741    7.741 demo.py:21(_translate1)

        1    0.000    0.000    7.741    7.741 {built-in method builtins.exec}

  5000000    1.052    0.000    1.052    0.000 {built-in method maketrans}

        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

  5000000    4.819    0.000    4.819    0.000 {method 'translate' of 'str' objects}

### translate2

         5000004 function calls in 5.284 seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)

        1    0.000    0.000    5.284    5.284 <string>:1(<module>)

        1    0.702    0.702    5.284    5.284 demo.py:31(_translate2)

        1    0.000    0.000    5.284    5.284 {built-in method builtins.exec}

        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

  5000000    4.582    0.000    4.582    0.000 {method 'translate' of 'str' objects}

### translate3

         5000004 function calls in 3.548 seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)

        1    0.000    0.000    3.548    3.548 <string>:1(<module>)

        1    0.720    0.720    3.548    3.548 demo.py:36(_translate3)

        1    0.000    0.000    3.548    3.548 {built-in method builtins.exec}

        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

  5000000    2.828    0.000    2.828    0.000 {method 'translate' of 'str' objects}

### translate4

         5000004 function calls in 5.751 seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)

        1    0.000    0.000    5.751    5.751 <string>:1(<module>)

        1    0.722    0.722    5.751    5.751 demo.py:41(_translate4)

        1    0.000    0.000    5.751    5.751 {built-in method builtins.exec}

        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

  5000000    5.029    0.000    5.029    0.000 {method 'translate' of 'str' objects}

基准测试2

时间消耗:

• tx2 < tx3 < tx1 < tx4
• t2 < t3 < t1 < t4

a = '你好的\r\n打分a\r\tdeadaaes\r\n\tttttrb'

k = ('\r', '\n', '\t')

def t1(text):

    for ch in k:

        if ch in text:

            text = text.replace(ch, ' ')

    return text

def t2(old_value1):

    # data reformat

    old_value2 = old_value1.replace('\t', ' ')

    old_value3 = old_value2.replace('\n', ' ')

    return old_value3.replace('\r', ' ')

def t3(old_value):

    # data reformat

    old_value = old_value.replace('\t', ' ')

    old_value = old_value.replace('\n', ' ')

    return old_value.replace('\r', ' ')

def t3_1(old_value):

    # data reformat

    return old_value.replace('\r', ' ').replace('\t', ' ').replace('\n', ' ')

def t4(s):

    t = s.maketrans("\n\t\r", "   ")

    return s.translate(t)

def tx1(x):

    for i in range(0, 100000):

        t1(x)

def tx2(x):

    for i in range(0, 100000):

        t2(x)

def tx3(x):

    for i in range(0, 100000):

        t3(x)

def tx3_1(x):

    for i in range(0, 100000):

        t3_1(x)

def tx4(x):

    for i in range(0, 100000):

        t4(x)

tx1(a)

tx2(a)

tx3(a)

tx3_1(a)

tx4(a)

Profile:

https://stackoverflow.com/questions/3411771/best-way-to-replace-multiple-characters-in-a-string