How to discard part of the fraction after the dot?

Question

Python

Good afternoon!
Tell me how in python3 to discard part of the fraction after the point, indicating how many characters should be. By analogy with round, only it does not fit because it rounds up.
For example:
>>> var1 = round(0.0019, 3)
>>> print(var1)
0.002
and you need 0.001
It is not known in advance how many characters there will be, maybe 0.2342354324 or maybe 0.1 should work correctly.
Thank you!

Answer 1

Some fierce Bangalore star marked with a solution (

def truncate(f, n):
    s = "%.20f" % f
    return s[:s.find('.') + n + 1]