Perl help

[Bill Mullen]

Erik Price said:
>
> Cole Tuininga wrote:
>> Got a perl question for y'all.  I rarely have to do anything with
>> perl, and I'm sure perl has a good reason for behaving like the
>> following, but heck if I can figure it out.
>>
>> The perl cookbook suggestions using sprintf for rounding floats.  This
>> seemingly works fine:
>>
>> egon at trogdor:~$ perl -e 'print sprintf( "%.2f\n", 0.562 )'
>> 0.56
>> egon at trogdor: perl -e 'print sprintf( "%.2f\n", 0.567 )'
>> 0.57
>>
>> However, I'm extremely confused by the following:
>>
>> egon at trogdor:~$ perl -e 'print sprintf( "%.2f\n", 0.565 )'
>> 0.56
>
> I don't have an answer, Cole, but the same happens in Python and I'd bet
>  in C as well -- must be a convention of the printf routines:
>
> Python 2.2.2 (#1, Mar  9 2003, 08:18:26)
> [GCC 3.2 20020927 (prerelease)] on cygwin
> Type "help", "copyright", "credits" or "license" for more information.
>  >>> print "%.2f\n" % 0.562
> 0.56
>
>  >>> print "%.2f\n" % 0.567
> 0.57
>
>  >>> print "%.2f\n" % 0.565
> 0.56

It's kind of a kludge, but perhaps adding some very small value such as
0.00001 just prior to the rounding will get the result you want?

moon at tvbox:~$ perl -e 'print sprintf( "%.2f\n", 0.56501 )'
0.57

-- 
Bill Mullen   moon at lunarhub.com   MA, USA   RLU #270075   MDK 8.1 & 9.0
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