trouble with using variables as format precision

Question

I have been trying to use a variable as a specifer in float precision to try to limit the number of decimal places shown for pi:

num = float(input("What decimal point do you want pi to be displayed to?(Up to 15) "))

print(format(math.pi, '.(num)f'))

when i run it, it shows the ValueError: Format specifier missing precision

I was wondering if there was any other way of writing it so i would be able to use a variable. Im pretty new and its probably a really simple mistake, but i dont know.

Thanks for any help :D

Answer 1

you can just pass it in as a format argument ...

num="3"
print("{pi:0.{num}f}".format(pi=22/7.0,num=num))