How can I round up the number of periodic digits?

Question

I have two numbers, one I get by calculating it and the other one I bring it from the database.

calculated = 2.183333333333333
database   = 2.18333333333333

But when I compare them to know if they are the same, I return False when it should be True.

There is some way to limit the number of periodic numbers, but not to affect decimals that are not periodic, for example:

2.1748888888888 -> 2.1748
1.23333333      -> 1.23

To factor in minor differences: `abs(calculated - database) < epsilon`, pick an epsilon that works for you. A slightly more flexible version of this is built into the `math` module. — user3483203, Jul 05 '19 at 21:39
2.1748888888888 -> 2.1748 is just wrong. It should be 2.17489 or 2.1749 unless you don't plan on using it for any calculations. — Alain T., Jul 05 '19 at 21:43

score 2 · Accepted Answer · answered Jul 05 '19 at 21:46

You could use the math.isclose method:

>>> from math import isclose
>>> calculated = 2.183333333333333
>>> database   = 2.18333333333333
>>> isclose(calculated, database)
True

This allows for setting the relative tolerance and minimum absolute tolerance as well refer to the docs for more explanation.

1 Answers1