CODEWITHSUNDEEP
pythonstringtemplatequine
Goby
Goby

Reputation: 57

Using string templates for making a quine in python?

I'm basically trying to make a quine in python and first tried with f-strings, but I quickly realized that I first have to define the variables I want to format inside the string. I then learned about string templates and figured that would be the way to go. I am however not that experienced with it and could need some help. Any suggestions?

Here's the actual code:

from string import Template
s="from string import Template\ns=$s\nt=Template($s).substitute(s=$s)\nprint($s)"
t=Template(s).substitute(s=s)
print(s)

It gives me somewhat of the right result. The only problem is that it's not replacing the $s with the actual string. I've might just have misunderstood the whole concept with quines and the method of doing them but I feel this should work.

Output:

from string import Template
s=$s
t=Template($s).substitute(s=$s)
print($s)

Upvotes: 4

Views: 431

Answers (2)

Goby
Goby

Reputation: 57

I've taken the advice from @Will Da Silva and included the repr() function in my method of doing it as seen below:

from string import Template
s='from string import Template\ns=$s\nt=Template(s)\nprint(t.substitute(s=repr(s)))'
t=Template(s)
print(t.substitute(s=repr(s)))

I think the problem was that it interpreted the string as code and in turn made a new line at every \n. But now when it keeps the quotation marks it just sees it as a string.

Upvotes: 0

Will Da Silva
Will Da Silva

Reputation: 7040

I'm not sure how this would be done using string.Template, but you could use str.format as a straightforward replacement to f-strings that suits this task, as it allows you to delay the interpolation of the s variable:

s='s={0!r}\nprint(s.format(s))'
print(s.format(s))

Output:

s='s={0!r}\nprint(s.format(s))'
print(s.format(s))

The !r is used to get the repr of s, which wraps it in quotes, and escapes the newlines.

Upvotes: 5

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