Consider a String a f-string in Python

Question

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'

Answer 1

Remve the double quotations that should fix the issue because the f in a f string needs to be outside the actuall string

Answer 2

You are missing two concepts.

1. 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"

2. Whatever you have between {}, it will be a previously defined variable:

x = "something"
f"this will be {x}"

Answer 3

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'.

Answer 4

You'd do this -

x = 3
s = f'12{x}4'

Answer 5

This can also work.

x = 3 
s = "12{}4"
print(s.format(x))

Answer 6

Just remove extra commas

s = f'12{x}4'

Answer 7

x = 3 
s = '12{}4'.format(x)

or

x = 3 
print('12%s4' %x)