python-3.x 为什么“this”模块中的文本是ROT13编码的?

ss2ws0br  于 2023-11-20  发布在  Python
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如果我们打开Python解释器并输入import this,它将打印 Zen of python。从Python source code中,此文本由以下代码生成。

s = """Gur Mra bs Clguba, ol Gvz Crgref

Ornhgvshy vf orggre guna htyl.
Rkcyvpvg vf orggre guna vzcyvpvg.
Fvzcyr vf orggre guna pbzcyrk.
Pbzcyrk vf orggre guna pbzcyvpngrq.
Syng vf orggre guna arfgrq.
Fcnefr vf orggre guna qrafr.
Ernqnovyvgl pbhagf.
Fcrpvny pnfrf nera'g fcrpvny rabhtu gb oernx gur ehyrf.
Nygubhtu cenpgvpnyvgl orngf chevgl.
Reebef fubhyq arire cnff fvyragyl.
Hayrff rkcyvpvgyl fvyraprq.
Va gur snpr bs nzovthvgl, ershfr gur grzcgngvba gb thrff.
Gurer fubhyq or bar-- naq cersrenoyl bayl bar --boivbhf jnl gb qb vg.
Nygubhtu gung jnl znl abg or boivbhf ng svefg hayrff lbh'er Qhgpu.
Abj vf orggre guna arire.
Nygubhtu arire vf bsgra orggre guna *evtug* abj.
Vs gur vzcyrzragngvba vf uneq gb rkcynva, vg'f n onq vqrn.
Vs gur vzcyrzragngvba vf rnfl gb rkcynva, vg znl or n tbbq vqrn.
Anzrfcnprf ner bar ubaxvat terng vqrn -- yrg'f qb zber bs gubfr!"""

d = {}
for c in (65, 97):
    for i in range(26):
        d[chr(i+c)] = chr((i+13) % 26 + c)

print "".join([d.get(c, c) for c in s])

字符串
我已经阅读了What is the source code of the "this" module doing?从接受的答案,我明白了s变量文本是ROT13编码和最后6行

d = {}
for c in (65, 97):
    for i in range(26):
        d[chr(i+c)] = chr((i+13) % 26 + c)

print "".join([d.get(c, c) for c in s])


将通过建立翻译表并打印到控制台来解码。
为什么它被编码?换句话说,为什么它不是这样写的:

s = """
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!"""

print(s)


注:我在SO中搜索了类似的问题,但找不到有用的链接。

hwazgwia

hwazgwia1#

来自@abarnert的这条评论说明了一切:
作为一个笑话。模块所做的一切,从混淆源代码到从头开始实现rot 13,即使它内置在stdlib中,都直接违反了Python的Zen。Tim Peters还偷偷地在Zen本身中开了一些微妙的玩笑(注意TOOWTDI行上的破折号有两种不同的方式?)
而且,efforts were made to remove the encoding,但它是rolled back in a subsequent PR

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