我叫random.seed(234),然後調用random.randint(0,99),並收到92.當我再次重複這個過程多次我收到86.當我打電話random.randint第二次然後它返回92.我期待的第一個值是86而不是92.爲什麼是92?Python random.seed表現奇怪
完整的日誌輸出如下。我已經包括它的所有櫃面有以前的一些動作可以解釋看似錯誤行爲:
In [1]: import random
In [2]: import string
In [3]: string.letters
Out[3]: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
In [4]: string.ascii_letters
Out[4]: 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
In [5]: string.printable
Out[5]: 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!"#$%&\'()*+,-./:;<=>[email protected][\\]^_`{|}~ \t\n\r\x0b\x0c'
In [6]: len(string.printable)
Out[6]: 100
In [7]: [string.printable[random.randint(0,99)] for i in range(20)]
Out[7]:
['{',
'+',
'[',
'\r',
'R',
'Z',
'v',
'|',
'v',
'e',
'T',
'x',
'\\',
'}',
'0',
'>',
'V',
'\n',
'`',
'`']
In [8]: ''.join([string.printable[random.randint(0,99)] for i in range(20)])
Out[8]: '%Z\\%mx4Z53uUZIa5KHe*'
In [9]: ''.join([string.printable[random.randint(0,99)] for i in range(20)])
Out[9]: 'Fg\nDHW+oV?-9``}\x0by%xD'
In [10]: import os
In [11]: os.urandom(1)
Out[11]: '('
In [12]: os.urandom(1)
Out[12]: '8'
In [13]: os.urandom(1)
Out[13]: '\xb1'
In [14]: os.urandom(1)
Out[14]: ')'
In [15]: os.urandom(1)
Out[15]: '\x8c'
In [16]: os.urandom(1)
Out[16]: '^'
In [17]: os.urandom(1)
Out[17]: '{'
In [18]: os.urandom(1)
Out[18]: '\x8f'
In [19]: ''.join(os.urandom(10))
Out[19]: '{t\x8dR\x1d\x83\xef\xd6N\xbd'
In [20]: ''.join(os.urandom(10))
Out[20]: '\x96\\\xf6\xe3\xf4/\x1f\xc7\x90\x02'
In [21]: from random import SystemRandom
In [22]: crypt = SystemRandom()
In [23]: ''.join([string.printable[crypt.randrange(100)] for i in range(20)])
Out[23]: "WoDVH\r1!?1+djB'f<;nW"
In [24]: ''.join([string.printable[crypt.randrange(100)] for i in range(20)])
Out[24]: '\rf?zo`7^{Y_Zx^[SYw7c'
In [25]: ''.join([string.printable[crypt.randrange(100)] for i in range(20)])
Out[25]: "3k*uGVIP'~^{P*~bserk"
In [26]: ''.join([string.printable[crypt.randrange(100)] for i in range(20)])
Out[26]: '~lkM/a&#_F&D\n<sC&i\r\n'
In [27]: random.seed(234)
In [28]: random.randint(0,99)
Out[28]: 92
In [29]: random.seed(234)
In [30]: random.randint(0,99)
Out[30]: 86
In [31]: random.seed(234)
In [32]: random.randint(0,99)
Out[32]: 86
In [33]: random.seed(234)
In [34]: random.randint(0,99)
Out[34]: 86
In [35]: random.randint(0,99)
Out[35]: 92
In [36]: random.randint(0,99)
Out[36]: 48
In [37]: random.seed(234)
In [38]: random.randint(0,99)
Out[38]: 86
In [39]: import sys
In [40]: sys.version_info
Out[40]: sys.version_info(major=2, minor=7, micro=13, releaselevel='final', serial=0)
In [41]: sys.version
Out[41]: '2.7.13 (default, Dec 17 2016, 23:03:43) \n[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)]'
** 編輯,怪異:「相同」看似錯誤行爲重複 ** 在同一個終端窗口我關閉了以前的ipython會話。我做了一些命令行活動,然後我再次打開ipython。我做了一些不同的工作。然後我又試了這一點:
In [37]: import random
In [38]: random.seed(234)
In [39]: random.randint(0, 99)
Out[39]: 85
In [40]: random.randint(0, 99)
Out[40]: 50
In [41]: random.seed(234)
In [42]: random.randint(0, 99)
Out[42]: 86
In [43]: random.randint(0, 99)
Out[43]: 92
蟒蛇3.4'>>>隨機的。種子(234) >>> random.randint(0,99) >>> random.seed(234) >>> random.randint(0,99) >>> random.seed( 234) >>> random.randint(0,99) 43'。無法重現。 –
python 2.7測試,不同的值,但每次都相同... –
是的,很奇怪。謝謝@ Jean-FrançoisFabre,我想這是一個邊緣案例錯誤或記錄但令人驚訝的行爲。 – AJP