如何在python中生成8个字节的唯一随机数? [英] How to generate 8 bytes unique random number in python?

问题描述

有什么方法可以生成Python语言中 8个字节大小的唯一随机数?我使用了UUID库，但它的 16个字节与我的要求不符.

Is there any way to generate a unique random number that has 8 bytes size in python language? I used the UUID library but it has 16 bytes which are not aligned with my requirement.

任何帮助将不胜感激.

预先感谢

推荐答案

嗯，您可以使用线性同余生成器，通过正确选择参数，可以生成从u64到u64的完美映射.换句话说，如果您可以访问先前的8个字节的UUID，则可以生成合理的随机的接下来的8个字节的UUID，而无需重复，直到整个2 ⁶⁴ 空间ix耗尽为止.它也可以在O(log(N))中向前和向后N步.

Well, you could use Linear Congruential Generator which, with proper selection of parameters, produce perfect mapping from u64 to u64. In other words, if you have access to previous 8bytes UUID, you could generate reasonable random next 8bytes UUID WITHOUT REPETITIONS till whole 2⁶⁴ space ix exhausted. It could also go backward and forward N steps in O(log(N)).

使用NumPy，Python 3.7，Anaconda，Win 10 x64编写的代码

Code using NumPy, Python 3.7, Anaconda, Win 10 x64

#%%
import numpy as np

#%%
class LCG(object):

    UZERO: np.uint64 = np.uint64(0)
    UONE : np.uint64 = np.uint64(1)

    def __init__(self, seed: np.uint64, a: np.uint64, c: np.uint64) -> None:
        self._seed: np.uint64 = np.uint64(seed)
        self._a   : np.uint64 = np.uint64(a)
        self._c   : np.uint64 = np.uint64(c)

    def next(self) -> np.uint64:
        self._seed = self._a * self._seed + self._c
        return self._seed

    def seed(self) -> np.uint64:
        return self._seed

    def set_seed(self, seed: np.uint64) -> np.uint64:
        self._seed = seed

    def skip(self, ns: np.int64) -> None:
        """
        Signed argument - skip forward as well as backward

        The algorithm here to determine the parameters used to skip ahead is
        described in the paper F. Brown, "Random Number Generation with Arbitrary Stride,"
        Trans. Am. Nucl. Soc. (Nov. 1994). This algorithm is able to skip ahead in
        O(log2(N)) operations instead of O(N). It computes parameters
        A and C which can then be used to find x_N = A*x_0 + C mod 2^M.
        """

        nskip: np.uint64 = np.uint64(ns)

        a: np.uint64 = self._a
        c: np.uint64 = self._c

        a_next: np.uint64 = LCG.UONE
        c_next: np.uint64 = LCG.UZERO

        while nskip > LCG.UZERO:
            if (nskip & LCG.UONE) != LCG.UZERO:
                a_next = a_next * a
                c_next = c_next * a + c

            c = (a + LCG.UONE) * c
            a = a * a

            nskip = nskip >> LCG.UONE

        self._seed = a_next * self._seed + c_next


#%%
np.seterr(over='ignore')

a = np.uint64(6364136223846793005)
c = np.uint64(1)

seed = np.uint64(1)

rng64 = LCG(seed, a, c)

print(rng64.next())
print(rng64.next())
print(rng64.next())

#%%
rng64.skip(-3) # back by 3
print(rng64.next())
print(rng64.next())
print(rng64.next())

rng64.skip(-3) # back by 3
rng64.skip(2) # forward by 2
print(rng64.next())

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