Help me please : Rounding-down numbers
Erik Max Francis
max at alcyone.com
Thu Mar 27 01:33:15 EST 2003
Bengt Richter wrote:
> On Wed, 26 Mar 2003 18:19:14 -0800, Erik Max Francis <max at alcyone.com>
> wrote:
>
> > Note that math.floor and int don't have quite the same behavior
> > (glossing over the obvious difference that the former returns a
> > float)
> > for the case of negative numbers.
>
> E.g.,
>
> >>> map(int,[-1.9, -1.5, -1.1, -0.5, 0.0, 0.5, 1.1, 1.5, 1.9])
> [-1, -1, -1, 0, 0, 0, 1, 1, 1]
> >>> from math import floor
> >>> map(floor,[-1.9, -1.5, -1.1, -0.5, 0.0, 0.5, 1.1, 1.5, 1.9])
> [-2.0, -2.0, -2.0, -1.0, 0.0, 0.0, 1.0, 1.0, 1.0]
Indeed. Technically, float(int(x)) rounds toward zero, whereas
math.floor(x) rounds toward negative infinity.
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Erik Max Francis / max at alcyone.com / http://www.alcyone.com/max/
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