如何计算组合的百分比？

Question

我有这个密码生成器，它从包含小写字母、大写字母和数字（不带 0）的列表中计算长度为 2 到 6 个字符的组合 - 总共 61 个字符。

我只需要显示已创建组合的百分比（步长为 5）。我试图计算所选长度的所有组合，从该数字一个边界值（5％步长值）并计算文本文件中写入的每个组合，当组合计数满足边界值时，打印 xxx % completed, 但此代码似乎不起作用。

请问您知道如何轻松显示百分比吗？

抱歉我的英语不好，我不是母语人士。

谢谢大家！

def pw_gen(characters, length):

    """generate all characters combinations with selected length and export them to a text file"""

    # counting number of combinations according to a formula in documentation
    k = length
    n = len(characters) + k - 1
    comb_numb = math.factorial(n)/(math.factorial(n-length)*math.factorial(length))

    x = 0

    # first value
    percent = 5

    # step of percent done to display
    step = 5

    # 'step' % of combinations
    boundary_value = comb_numb/(100/step)

    try:
        # output text file
        with open("password_combinations.txt", "a+") as f:
            for p in itertools.product(characters, repeat=length):
                combination = ''.join(p)

                # write each combination and create a new line
                f.write(combination + '\n')
                x += 1

                if boundary_value <= x <= comb_numb:
                    print("{} % complete".format(percent))
                    percent += step
                    boundary_value += comb_numb/(100/step)

                elif x > comb_numb:
                    break

Answer 1

首先 - 我认为您使用的组合公式不正确，因为 itertools.product 会产生重复变化，因此正确的公式是 n^k（n 的 k 次方）。

此外，您将百分比计算过于复杂了一点。我刚刚修改了您的代码以按预期工作。

import math
import itertools

def pw_gen(characters, length):
    """generate all characters combinations with selected length and export them to a text file"""

    k = length
    n = len(characters)
    comb_numb = n ** k

    x = 0
    next_percent = 5
    percent_step = 5

    with open("password_combinations.txt", "a+") as f:
        for p in itertools.product(characters, repeat=length):
            combination = ''.join(p)

            # write each combination and create a new line
            f.write(combination + '\n')
            x += 1

            percent = 100.0 * x / comb_numb
            if percent >= next_percent:
                print(f"{next_percent} % complete")
                while next_percent < percent:
                    next_percent += percent_step

棘手的部分是一个 while 循环，它确保对于非常小的集合（其中一个组合超过结果的 step 百分比）一切都能正常工作。

Answer 2

已删除 try:，因为您没有处理 expect 的任何错误。也删除了 elif:，这个条件无论如何都不会满足。此外，您的 comb_numb 公式不正确，因为您正在生成重复组合。通过这些更改，您的代码很好。

import math, iterations, string
def pw_gen(characters, length):

    """generate all characters combinations with selected length and export them to a text file"""

    # counting number of combinations according to a formula in documentation
    comb_numb = len(characters) ** k

    x = 0

    # first value
    percent = 5

    # step of percent done to display
    step = 5

    # 'step' % of combinations
    boundary_value = comb_numb/(100/step)
    # output text file
    with open("password_combinations.txt", "a+") as f:
        for p in itertools.product(characters, repeat=length):
            combination = ''.join(p)
            # write each combination and create a new line
            f.write(combination + '\n')
            x += 1
            if boundary_value <= x:
                print("{} % complete".format(percent))
                percent += step
                boundary_value += comb_numb/(100/step)

pw_gen(string.ascii_letters, 4)

如何计算组合的百分比？

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