Place value jumps wildly! Possible bug

[lsf22]

Renpy 8.03.22090809 (Python 3) (Linux)

Is it only occurring with the python 3 versions because this persisted with previous python 3 versions of Renpy? Whenever a number vaule gets added after a few times when it comes to decimals it jumps way up to a point where it should not.

For example on my test. I added a value of 0.4 a couple of times (3 times) till it created that anomaly

As you can see from the image that is attached. In the meantime how do I fix this?

[Mihara]

This is actually correct, funny as it sounds. See https://docs.python.org/3.9/tutorial/floatingpoint.html for a deeper discussion of the reasons, but it has to do with how floating point numbers are stored internally.

Code: Select all

$ python
Python 3.8.10 (default, Jun 22 2022, 20:18:18)
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 0.4 + 0.4 + 0.4
1.2000000000000002
>>>
$ python2
Python 2.7.18 (default, Jul  1 2022, 12:27:04)
[GCC 9.4.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 0.4 + 0.4 + 0.4
1.2000000000000002

I do wonder why the 2.7-based versions of RenPy don't do that, actually, but the correct solution is to limit the number of digits on display anyway.

[lsf22]

What can I do to prevent that from happening. It really screws up with how stats look in the renpy project I'm working on.
Does anyone have a solution?

[Mihara]

Just add a format specifier when actually displaying the number:

Code: Select all

$ f = 0.4 + 0.4 + 0.4
"This line limits the [f:.2] to two digits after the decimal."

See https://peps.python.org/pep-3101/#format-specifiers for details. Or https://sahiljain444.medium.com/format- ... 1df860a6a4 for a more readable explanation.

[lsf22]

I added that to one of my stats and it resulted in the following error: "Precision not allowed in integer format specifier"

example:

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frame:
        xpos 200
        ypos 20
        vbox:
            spacing 5
            text "Affection  [affection_g1:.2]" size 45 color "000000"

[Mihara]

You were trying to print an integer number as if it had decimals. Which is bogus so it's complaining. You can force it anyway: Replace ":.2" with ":.2f" and it will convert integers to float before trying to print them.