Deciphering Python’s “import this”
Among well known Easter eggs, Python embeds a library for displaying its famous PEP 20, called Zen of Python, which consists in 19 aphorisms giving guidelines to Python programmers.
Print Zen of Python
You can print the 19 aphorisms by simply importing this .
import thisThis outputs
The Zen of Python, by Tim PetersBeautiful 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!
Deciphering Zen of Python
There is actually more to this. Four variables are provided by the module: this.c, this.d, this.i, and this.s. this.s contains an encrypted version of Zen of Python, using a permutation of the alphabet, that can be recovered in this.d dictionary. print(this.s) gives
Gur Mra bs Clguba, ol Gvz CrgrefOrnhgvshy 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!
Let’s decipher it
import this
deciphered = ""
for c in this.s:
try:
decrypted += this.d[c]
except: # If the symbol is not encrypted
decrypted += c
print(deciphered)Conclusion
That’s it for this amusing easter egg! As parting note, to understand how Zen of Python embeds the philosophy of Python, consider “practicality beats purity”. This statement takes shape in the design of the len function, which is an exception among special methods, as it can be used as such, for practicality reasons, when implementing your own classes, but is implemented to a C++ level when used on basic data structures such lists, sets and dictionaries, for speed.
