From: Daniel Martin <martin@...>
Date: 2006-08-19T03:00:47+09:00
Subject: Re: Bug in sprintf?

Carlos <angus@quovadis.com.ar> writes:

> ara.t.howard@noaa.gov wrote:
>
>> On Sat, 19 Aug 2006, Wes Gamble wrote:
>>
>> so it's expected, documented, and consistent with c.
>
> It is not expected, nor documented, because the documentation of
> sprintf says:
>              d   | Convert argument as a decimal number.
>
> ...which is very explicit in that the argument will be interpreted as
> a decimal number, not octal.

I think that the problem here is that ruby is performing two
conversions, and the sprintf documentation only mentions one of them.

When you use '%d' in a sprintf(), ruby does a conversion of the
argument to an Integer using Kernel#Integer and then does the
conversion of the Integer to a portion of the output string as
documented.

Similarly, when you use %f in a sprintf(), ruby does a conversion of
the argument using Kernel#float and then does the conversion from
Float to part of the output string as documented.

So, we have:

   sprintf("%d",'08')      ==>   ArgumentError
   sprintf("%d",'8')       ==>   "8"
   sprintf("%d",'08'.to_i) ==>   "8"
   sprintf("%f",'08')      ==>   "8.000000"

I think that if you're hitting this quirk in actual code, your code
needs so .to_i dropped in a few places.  I'm actually surprised ruby
does those String=>Integer conversions at all.