Uncanny python math operations

Question

When I'm doing math or division operations in python I'll often get numbers like '297.40000000000003', how do I prevent this without using round() to simply the number to 297.4?

Answer 1

Unless you are going to perfom type coersion, you will not be able to _prevent_ default prescison. So, either round (without coersion) or string formatting.

Answer 2

If you need more precision, you can check out the decimal library.
It works also on sololearn.
https://docs.python.org/3/library/decimal.html

Answer 3

Branam ,

You can sometimes prevent the error by rearranging your formula so division happens last.

For example,

x = a / b * c # more likely to err

x = a * c / b # less likely to err

Answer 4

fairly simple to do yourself

n = input()
n_rounded = ""
for i,j in enumerate(n):
n_rounded += j
try:
if not int(j) and n.index(j,i,i+1)>n.index("."):
break
except:
pass