Suppose I have
x = 3
s = "f'12{x}4'"
How to consider s as f-string to print 1234, like writing print(f'12{x}4')
when I print s, it prints it as it as: f'12{x}4'
7 Answers
Remve the double quotations that should fix the issue because the f in a f string needs to be outside the actuall string
Comments
You are missing two concepts.
- The first one, is how you tell python your string is an f-string. The way to do this, is by adding the character 'f' before the first quotation mark:
f"this will be a f-string"
- Whatever you have between {}, it will be a previously defined variable:
x = "something"
f"this will be {x}"
Comments
Assuming you ask this because you can not use actual f-strings, but also don't want to pass the parameters explicitly using format, maybe because you do not know which parameter are in the not-really-an-f-string, and also assuming you don't want to use eval, because, well, eval.
You could pass the variables in the locals or globals scope to format:
>>> x = 3
>>> s = '12{x}4'
>>> s.format(**globals())
'1234'
>>> s.format(**locals())
'1234'
Depending on where s is coming from (user input perhaps?) This might still be a bit risky, though, and it might be better to define a dict of "allowed" variables and use that in format. As with globals and locals, any unused variables do not matter.
>>> vars = {"x": x, "y": y, "z": z}
>>> s.format(**vars)
Note that this does not give you the full power of f-strings, though, which will also evaluate expressions. For instance, the above will not work for s = '12{x*x}4'.
1 Comment
Mohamed Hicham Gaballah
This is what I mean yes, Thanks a lot It works!
You'd do this -
x = 3
s = f'12{x}4'
Comments
This can also work.
x = 3
s = "12{}4"
print(s.format(x))
Comments
x = 3
s = '12{}4'.format(x)
or
x = 3
print('12%s4' %x)
1 Comment
Niels Henkens
This is not an answer to the question...
print(eval(s))s=f'12{3}4'. It is not wrapped in quotation marks. Consider reading a tutorial about them.eval(s), but doing so would be very suspicious. Why exactly would you want this? What are you trying to achieve?scoming from?