Exponential Notation and integers

Timothy Fitz firemoth at gmail.com
Fri Nov 19 03:02:46 CET 2004

My comment is more of a linguistic complaint. The differences between
an integer (type int or long) and a float in practice are large,
shouldn't 1e100 be of an integer type, since it -is- an integer? The
default practice here of making it a float just seems wrong.

[Peter Hansen]
> Maybe something like this would help the OP:
> >>> def number(x):
> ...    return int(float(x))
> ...
> >>> MYCONSTANT = number('1.344e3')
> >>> print MYCONSTANT
> 1344

Yes, this would work in some cases, but not where it matters. Floats
have a significant amount of error when you are talking about very
large numbers, which is the only time you would want integer
exponential literals anyway, examples of errors:

>>> long(1e100)
>>> 1e20 == 10 ** 20 + 8192
>>> long(1e23) == 10 ** 23

The worst part is that because python will implicitly convert between
floats and integers, this can all happen silently and come back and
bite you where you least expect it.

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