f-string formula inside curly brackets not working

Question

I am on Python 3.7.

My code on line 3 works fine, however when I insert the underlying formula into line 4, my code returns the error:

SyntaxError: f-string: mismatched '(', '{', or '[' (the error points to the first '(' in line 4.

My code is:

cheapest_plan_point = 3122.54
phrase = format(round(cheapest_plan_point), ",")
print(f"1: {phrase}")
print(f"2: {format(round(cheapest_plan_point), ",")}")

I can't figure out what is wrong with line 4.

Answer 1

You used " quotes inside a "..." delimited string.

Python sees:

print(f"2: {format(round(cheapest_plan_point), "
      ,
      ")}")

so the )} is a new, separate string.

Use different delimiters:

print(f"2: {format(round(cheapest_plan_point), ',')}")

However, you don't need to use format() here. In an f-string, you already are formatting each interpolated value! Just add :, to apply the formatting instruction directly to the round() result:

print(f"2: {round(cheapest_plan_point):,}")

The format {expression:formatting_spec} applies formatting_spec to the outcome of expression, just as if you used {format(expression, 'formatting_spec')}, but without having to call format() and without having to put the formatting_spec part in quotes.