Python计数零

Question

我创建了一个代码,基本上生成一个随机的20位数字.代码如下:

import random
from random import randint

n=20

def digit(n):

    range_start = 10**(n-1)
    range_end = (10**n)-1
    return randint(range_start, range_end+1)


print(digit(n))

例如,此代码的输出是:

49690101904335902069

现在给出这段代码,我只是想知道如何计算输出中的零数,所以基本上我正在尝试创建一个名为的新函数count_zero():,但我不知道该把它放到我的参数和什么不是.

Answer 1

将数字转换为字符串并计算'0'字符数:

def count_zeros(number):
    return str(number).count('0')

演示:

>>> def count_zeros(number):
...     return str(number).count('0')
... 
>>> count_zeros(49690101904335902069)
5

或者不将其变成字符串:

def count_zeros(number):
    count = 0
    while number > 9:
        count += int(number % 10 == 0)
        number //= 10
    return count

后一种方法是很多慢但是:

>>> import random
>>> import timeit
>>> test_numbers = [random.randrange(10 ** 6) for _ in xrange(1000)]
>>> def count_zeros_str(number):
...     return str(number).count('0')
... 
>>> def count_zeros_division(number):
...     count = 0
...     while number > 9:
...         count += int(number % 10 == 0)
...         number //= 10
...     return count
... 
>>> timeit.timeit('[c(n) for n in test_numbers]',
...     'from __main__ import test_numbers, count_zeros_str as c', number=5000)
2.4459421634674072
>>> timeit.timeit('[c(n) for n in test_numbers]',
...     'from __main__ import test_numbers, count_zeros_division as c', number=5000)
7.91981315612793

要将它与您的代码结合起来,只需添加该功能,然后单独调用它; 你可以digit()直接传递结果或先存储结果,然后传入:

print(count_zeros(digit(n)))

或单独(允许您显示结果随机数):

result = digit(n)
zeros = count_zeros(result)
print('result', result, 'contains', zeros, 'zeros.')