使用timeit模块进行速度测试,使用profile模块进行性能统计,使用dis模块进行字节码反汇编.

下面的脚本演示了如何使用模块.

从输出中注意到的一件事是函数调用的数量会影响整体性能(当然,字节码指令的数量也是如此).

希望,(以及更多实验)应该为您提供有关如何提高功能效率的足够线索.

from timeit import timeit

from cProfile import runctx

from dis import dis

def analyse(*args):

victim = 'detartrated'

number = 1000

for func in args:

print('

%s

' % ('#' * 50))

name = func.__name__

print('test: %s(%r): %r' % (name, victim, func(victim)))

code = '%s(%r)' % (name, victim)

duration = timeit(

code, 'from __main__ import %s' % name, number=number)

usec = 1000000 * duration / number

print('time: %s: %.2f usec/pass

' % (code, usec))

runctx(code, globals(), locals())

dis(func)

def check_palin1(victim):

""" check progressively inner chars """

x = 0

# len/2 is num of iter needed for guarantee

while x < (len(victim)/2):

# on pass n, compare nth letter and nth to last letter

if victim[x+0] is victim[-(1+x)]:

# then increment the n counter

x += 1

else:

return False

return True

def check_palin2(victim):

""" check first and last chars repeatedly """

tmp = []

for i in victim:

# convert string into list

tmp.append(i)

# if 1 or 0 char left, palin is guaranteed

while len(tmp) > 1:

# if the first and last characters are the same letter

if tmp[0] is tmp[-1]:

# remove them both

tmp.pop(0)

tmp.pop(-1)

else:

return False

return True

def check_palin3(victim):

""" reverse string and compare to original using a loop """

tmp = ""

# for every letter

for i in victim:

# cat it to the beginning, not append

tmp = i + tmp

return tmp == victim

def check_palin4(victim):

""" reverse string and compare to original using slice syntax """

return victim == victim[::-1]

analyse(check_palin1, check_palin2, check_palin3, check_palin4)

输出：

##################################################

test: check_palin1('detartrated'): True

time: check_palin1('detartrated'): 3.80 usec/pass

9 function calls in 0.000 seconds

Ordered by: standard name

ncalls tottime percall cumtime percall filename:lineno(function)

1 0.000 0.000 0.000 0.000 :1()

1 0.000 0.000 0.000 0.000 test.py:20(check_palin1)

6 0.000 0.000 0.000 0.000 {len}

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

22 0 LOAD_CONST 1 (0)

3 STORE_FAST 1 (x)

24 6 SETUP_LOOP 72 (to 81)

>> 9 LOAD_FAST 1 (x)

12 LOAD_GLOBAL 0 (len)

15 LOAD_FAST 0 (victim)

18 CALL_FUNCTION 1

21 LOAD_CONST 2 (2)

24 BINARY_DIVIDE

25 COMPARE_OP 0 (

28 POP_JUMP_IF_FALSE 80

26 31 LOAD_FAST 0 (victim)

34 LOAD_FAST 1 (x)

37 LOAD_CONST 1 (0)

40 BINARY_ADD

41 BINARY_SUBSCR

42 LOAD_FAST 0 (victim)

45 LOAD_CONST 3 (1)

48 LOAD_FAST 1 (x)

51 BINARY_ADD

52 UNARY_NEGATIVE

53 BINARY_SUBSCR

54 COMPARE_OP 8 (is)

57 POP_JUMP_IF_FALSE 73

28 60 LOAD_FAST 1 (x)

63 LOAD_CONST 3 (1)

66 INPLACE_ADD

67 STORE_FAST 1 (x)

70 JUMP_ABSOLUTE 9

30 >> 73 LOAD_GLOBAL 1 (False)

76 RETURN_VALUE

77 JUMP_ABSOLUTE 9

>> 80 POP_BLOCK

31 >> 81 LOAD_GLOBAL 2 (True)

84 RETURN_VALUE

##################################################

test: check_palin2('detartrated'): True

time: check_palin2('detartrated'): 10.57 usec/pass

30 function calls in 0.000 seconds

Ordered by: standard name

ncalls tottime percall cumtime percall filename:lineno(function)

1 0.000 0.000 0.000 0.000 :1()

1 0.000 0.000 0.000 0.000 test.py:33(check_palin2)

6 0.000 0.000 0.000 0.000 {len}

11 0.000 0.000 0.000 0.000 {method 'append' of 'list' objects}

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

10 0.000 0.000 0.000 0.000 {method 'pop' of 'list' objects}

35 0 BUILD_LIST 0

3 STORE_FAST 1 (tmp)

36 6 SETUP_LOOP 27 (to 36)

9 LOAD_FAST 0 (victim)

12 GET_ITER

>> 13 FOR_ITER 19 (to 35)

16 STORE_FAST 2 (i)

38 19 LOAD_FAST 1 (tmp)

22 LOAD_ATTR 0 (append)

25 LOAD_FAST 2 (i)

28 CALL_FUNCTION 1

31 POP_TOP

32 JUMP_ABSOLUTE 13

>> 35 POP_BLOCK

40 >> 36 SETUP_LOOP 75 (to 114)

>> 39 LOAD_GLOBAL 1 (len)

42 LOAD_FAST 1 (tmp)

45 CALL_FUNCTION 1

48 LOAD_CONST 1 (1)

51 COMPARE_OP 4 (>)

54 POP_JUMP_IF_FALSE 113

42 57 LOAD_FAST 1 (tmp)

60 LOAD_CONST 2 (0)

63 BINARY_SUBSCR

64 LOAD_FAST 1 (tmp)

67 LOAD_CONST 3 (-1)

70 BINARY_SUBSCR

71 COMPARE_OP 8 (is)

74 POP_JUMP_IF_FALSE 106

44 77 LOAD_FAST 1 (tmp)

80 LOAD_ATTR 2 (pop)

83 LOAD_CONST 2 (0)

86 CALL_FUNCTION 1

89 POP_TOP

45 90 LOAD_FAST 1 (tmp)

93 LOAD_ATTR 2 (pop)

96 LOAD_CONST 3 (-1)

99 CALL_FUNCTION 1

102 POP_TOP

103 JUMP_ABSOLUTE 39

47 >> 106 LOAD_GLOBAL 3 (False)

109 RETURN_VALUE

110 JUMP_ABSOLUTE 39

>> 113 POP_BLOCK

48 >> 114 LOAD_GLOBAL 4 (True)

117 RETURN_VALUE

##################################################

test: check_palin3('detartrated'): True

time: check_palin3('detartrated'): 2.77 usec/pass

3 function calls in 0.000 seconds

Ordered by: standard name

ncalls tottime percall cumtime percall filename:lineno(function)

1 0.000 0.000 0.000 0.000 :1()

1 0.000 0.000 0.000 0.000 test.py:50(check_palin3)

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

52 0 LOAD_CONST 1 ('')

3 STORE_FAST 1 (tmp)

54 6 SETUP_LOOP 24 (to 33)

9 LOAD_FAST 0 (victim)

12 GET_ITER

>> 13 FOR_ITER 16 (to 32)

16 STORE_FAST 2 (i)

56 19 LOAD_FAST 2 (i)

22 LOAD_FAST 1 (tmp)

25 BINARY_ADD

26 STORE_FAST 1 (tmp)

29 JUMP_ABSOLUTE 13

>> 32 POP_BLOCK

57 >> 33 LOAD_FAST 1 (tmp)

36 LOAD_FAST 0 (victim)

39 COMPARE_OP 2 (==)

42 RETURN_VALUE

##################################################

test: check_palin4('detartrated'): True

time: check_palin4('detartrated'): 0.65 usec/pass

3 function calls in 0.000 seconds

Ordered by: standard name

ncalls tottime percall cumtime percall filename:lineno(function)

1 0.000 0.000 0.000 0.000 :1()

1 0.000 0.000 0.000 0.000 test.py:59(check_palin4)

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

61 0 LOAD_FAST 0 (victim)

3 LOAD_FAST 0 (victim)

6 LOAD_CONST 1 (None)

9 LOAD_CONST 1 (None)

12 LOAD_CONST 2 (-1)

15 BUILD_SLICE 3

18 BINARY_SUBSCR

19 COMPARE_OP 2 (==)

22 RETURN_VALUE