Odd ValueError using float

[emile]

On 03/14/2015 08:52 AM, Chris Angelico wrote:
> On Sun, Mar 15, 2015 at 2:28 AM, emile <emile at fenx.com> wrote:
>> It ran almost to completion before generating the error again --
>>
>> (Pdb) decval
>> '4'
>> (Pdb) type(decval)
>> <type 'str'>
>> (Pdb) len(decval)
>> 1
>> (Pdb) int(decval)
>> *** ValueError: invalid literal for int() with base 10: '41.700000000000003'
>>
>> So there's still something amiss.
>
> Compare these two lines' outputs:
>
> print("str %d, int %d" % (id(str), id(int)))
> print("str %d, int %d" % (id(type("")), id(type(0)))
>

(Pdb) print("str %d, int %d" % (id(str), id(int)))
str 505366496, int 505399904
(Pdb) print("str %d, int %d" % (id(type("")), id(type(0))))
str 505366496, int 505399904



> Any difference in id would indicate that the names have been shadowed
> - seems unlikely, but worth checking. And then, just to be absolutely
> sure:
>
> type(decval) is type("")

(Pdb) type(decval) is type("")
True


> There is another, and very nasty, possibility. If you're working with
> a C extension that has a refcount bug in it, all sorts of bizarre
> things can happen - crucial type objects getting garbage collected,
> objects getting disposed of and others taking their places, all kinds
> of weird and wonderful things. Normally that'll eventually cause a
> crash, but who knows...

Here're the imports:

import os, time, re, shutil, subprocess
from fenx.BBxXlate.bbxfile import BBxFile      # a pure python module
from fenx import RealPyOdbc2

and of course, pdb when I break for the error condition.

Emile