python incorrect rounding with floating point numbers

Question

>>> a = 0.3135
>>> print(\"%.3f\" % a)
0.314
>>> a = 0.3125
>>> print(\"%.3f\" % a)
0.312
>>>

I am exp

Answer 1

I had the same incorrect rounding

round(0.573175, 5) = 0.57317

My solution

def to_round(val, precision=5):
    prec = 10 ** precision
    return str(round(val * prec) / prec)

to_round(0.573175) = '0.57318'