Hi all
I have an object which represents a Decimal type.
It can receive input from various sources. It has to round the value to a
particular scale factor before storing it. The scale factor can vary, so it
has to be looked up every time, which is a slight overhead. I thought I
could speed it up a bit by checking first to see if the value has any
decimal places. If not, I can skip the scaling routine.
This is how I do it -
s = str(value)
if '.' in s:
int_portion, dec_portion = s.split('.')
is_integer = (int(int_portion) == value)
else:
is_integer = True
It assumes that the value is in the form iii.ddd or just iii. Today I found
the following value -
-1.4210854715202004e-14
which does not match my assumption.
It happens to work, but I don't understand enough about the notation to know
if this is reliable, or if there are any corner cases where my test would
fail.
I suspect that my test is a case of premature optimisation, and that I might
as well just scale the value every time. Still, I would be interested to
know if this could be a problem, or if there is a better way to do what I
want.
Thinking aloud, maybe this is a better test -
is_integer = (value == value.quantize(0))
Thanks
Frank Millman
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