mjhjmtu

I have the following f-string I want to print out on the condition the variable is available:

f"Percent growth: self.percent_growth if True else 'No data yet'"

Which results in:

Percent growth : 0.19824077757643577

So normally I'd use a type specifier for float precision like this:

f'self.percent_growth:.2f'

Which would result in:

0.198

But that messes with the if-statement in this case. Either it fails because:

f"Percent profit : self.percent_profit:.2f if True else 'None yet'"

The if statement becomes unreachable.
Or in the second way:

f"Percent profit : self.percent_profit if True else 'None yet':.2f"

The f-string fails whenever the condition leads to the else clause.

So my question is, how can I apply the float precision within the f-string when the f-string can result in two types?

You could use another f-string for your first condition:

f"Percent profit : f'self.percent_profit:.2f' if True else 'None yet'"

Admittedly not ideal, but it does the job.

I think the f string within f string answer is as simple as it gets, but if you want a little bit more readability, consider moving the condition outside the f string:

value = f'self.percent_profit:.2f' if True else 'No data yet'
print(f"Percent profit : value")

You can use a ternary for the formatter as well - no need to stack 2 f-strings like Nikolas answer does:

for pg in (2.562345678, 0.9, None): # 0.0 is also Falsy - careful ;o)
 print(f"Percent Growth: pg if pg else 'No data yet':'.05f' if pg else ''")
 # you need to put '.05f' into a string for this to work and not complain

Output:

Percent growth: 2.56235
Percent growth: 0.90000
Percent growth: No data yet