A use for integer quotients

[Christian Tanzer]

Just van Rossum <just at letterror.com> wrote:

> > As for the second line: do you really think
> > int(float(bytes)/float(k)+.5) is signigicantly better for rounding?
> 
> 1) only one of the / operands need to be a float to force a float
> outcome, and 2) there is a round() builtin function. Now, if we
> initialize k to a float, we can write it like so:
> 
>    int(round(bytes/k))

My version of the Python Library Reference Manual (Release 2.1, 15
April 2001) says:

    Conversion from floating point to (long or plain) integer may
    round or truncate as in C; see functions floor() and ceil() in the
    math module for well-defined conversions.

That means that one should not use `int` to convert from float to
integer. No using `int (math.floor (a/b))` is quite a mouthful but
everybody caring about version compatibility will have to use such
abominations for a long time. (For instance, my main customer will
ship based products on 1.5.2 for several month to come, the shift to
2.x *may* happen with the next major release which is planned for
the last quarter of the year).

-- 
Christian Tanzer                                         tanzer at swing.co.at
Glasauergasse 32                                       Tel: +43 1 876 62 36
A-1130 Vienna, Austria                                 Fax: +43 1 877 66 92