Fractions wrongly encoded about simplejson HOT 4 CLOSED

0.3 does not have an exact floating point representation, and the version of Python you're using doesn't use a clever algorithm to compactly repr floats.

If you use Decimal('0.3') which is exactly 0.3 then you will get the expected output.

from simplejson.

Here's some more evidence:

In [1]: repr(0.3)
Out[1]: '0.29999999999999999'

In [2]: 0.29999999999999999 == 0.3
Out[2]: True

If this doesn't make sense to you, I suggest reading up on how floating point works (IEEE 754).

from simplejson.

I do understand the issue, but I don't agree that nothing should be done to work around it. Converting to string rather than just doing a repr yields the correct human-readable (and JavaScript-readable) string.

In [1]: str(0.3)
Out[1]: '0.3'

In [2]: str(0.29999999999999999)
Out[2]: '0.3'

But at the end of the day, it's your code, and if you don't think this issue should be fixed, then no worries - I will continue to work around it as I am at present.

from simplejson.

Sorry, but that is no good. str(f) is lossy for floats, so it can not be used.

>>> import math
>>> float(str(math.pi)) == math.pi
False
>>> float(repr(math.pi)) == math.pi
True

This is more of an issue with Python than simplejson.

from simplejson.