Rails - Oct 2007 - Problem with display of float types

Hello all,

I am taking some values from mysql columns of type float (16, 2) ,
performing a calculation such as multiply or divide, before displaying
on screen, and then displaying on a screen.

Unfortunately, sometimes the value has many decimal places displayed!
(Eg 136.5325325) Is there a way I can limit it to only display 2
decimal places?

Thanks,
Charles


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hi,
    if you only wanna display it precisely as you wish, use "printf"

Br



On 10月4日, 上午10时03分,
"charles.poul...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org"
<charles.poul...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> Hello all,
>
> I am taking some values from mysql columns of type float (16, 2) ,
> performing a calculation such as multiply or divide, before displaying
> on screen, and then displaying on a screen.
>
> Unfortunately, sometimes the value has many decimal places displayed!
> (Eg 136.5325325) Is there a way I can limit it to only display 2
> decimal places?
>
> Thanks,
> Charles

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Think theres a bit missing off the end?

Can I use printf inside a rhtml?

Charles

On Oct 4, 3:45 pm, myst_tt
<tdxia...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> hi,
>     if you only wanna display it precisely as you wish, use
"printf"
>
> Br
>
> On 10月4日, 上午10时03分,
"charles.poul...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org"
>
> <charles.poul...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > Hello all,
>
> > I am taking some values from mysql columns of type float (16, 2) ,
> > performing a calculation such as multiply or divide, before displaying
> > on screen, and then displaying on a screen.
>
> > Unfortunately, sometimes the value has many decimal places displayed!
> > (Eg 136.5325325) Is there a way I can limit it to only display 2
> > decimal places?
>
> > Thanks,
> > Charles

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On Oct 4, 2007, at 3:57 AM,
charles.poulsen-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
wrote:
> Think theres a bit missing off the end?
>
> Can I use printf inside a rhtml?
>
> Charles
Of course you can, it''s just Ruby.  If you want to stay with a Rails  
solution, try number_with_precision(136.5325325, 2)
(and then look at the source for that method and you won''t need the  
method anymore)

-Rob
> On Oct 4, 3:45 pm, myst_tt
<tdxia...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> hi,
>>     if you only wanna display it precisely as you wish, use
"printf"
>>
>> Br
>>
>> On 10月4日, 上午10时03分,
"charles.poul...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org"
>>
>> <charles.poul...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>>> Hello all,
>>
>>> I am taking some values from mysql columns of type float (16, 2) ,
>>> performing a calculation such as multiply or divide, before  
>>> displaying
>>> on screen, and then displaying on a screen.
>>
>>> Unfortunately, sometimes the value has many decimal places  
>>> displayed!
>>> (Eg 136.5325325) Is there a way I can limit it to only display 2
>>> decimal places?
>>
>>> Thanks,
>>> Charles
Rob Biedenharn		http://agileconsultingllc.com
Rob-xa9cJyRlE0mWcWVYNo9pwxS2lgjeYSpx@public.gmane.org




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On Oct 4, 6:52 am, Rob Biedenharn
<R...-xa9cJyRlE0mWcWVYNo9pwxS2lgjeYSpx@public.gmane.org> wrote:
> Of course you can, it''s just Ruby.  If you want to stay with a
Rails
> solution, try number_with_precision(136.5325325, 2)
> (and then look at the source for that method and you won''t need
the
> method anymore)
number_with_precision doesn''t round correctly, though. From the
source:

      # Formats a +number+ with the specified level of +precision+
(e.g., 112.32 has a precision of 2). The default
      # level of precision is 3.
      #
      # ==== Examples
      #  number_with_precision(111.2345)     # => 111.235
      #  number_with_precision(111.2345, 2)  # => 111.24
      #  number_with_precision(13, 5)        # => 13.00000
      #  number_with_precision(389.32314, 0) # => 389
      def number_with_precision(number, precision=3)
        "%01.#{precision}f" % number
      rescue
        number
      end

111.2345 to two decimal places should be 111.23, not 111.24.


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On Oct 4, 2007, at 2:22 PM, Stan Kaufman wrote:
>
> On Oct 4, 6:52 am, Rob Biedenharn
<R...-xa9cJyRlE0mWcWVYNo9pwxS2lgjeYSpx@public.gmane.org> wrote:
>
>> Of course you can, it''s just Ruby.  If you want to stay with a
Rails
>> solution, try number_with_precision(136.5325325, 2)
>> (and then look at the source for that method and you won''t
need the
>> method anymore)
>
> number_with_precision doesn''t round correctly, though. From the
> source:
>
>       # Formats a +number+ with the specified level of +precision+
> (e.g., 112.32 has a precision of 2). The default
>       # level of precision is 3.
>       #
>       # ==== Examples
>       #  number_with_precision(111.2345)     # => 111.235
>       #  number_with_precision(111.2345, 2)  # => 111.24
>       #  number_with_precision(13, 5)        # => 13.00000
>       #  number_with_precision(389.32314, 0) # => 389
>       def number_with_precision(number, precision=3)
>         "%01.#{precision}f" % number
>       rescue
>         number
>       end
>
> 111.2345 to two decimal places should be 111.23, not 111.24.
The doc is wrong -- probably written by a human ;-)

$ script/console
Loading development environment.
 >> helper.number_with_precision(111.2345, 2)
=> "111.23"

I suspect the aforementioned human applied the precision=2 to the  
result of the precision=3 shown just above it rather than the  
original 111.2345 argument.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob-xa9cJyRlE0mWcWVYNo9pwxS2lgjeYSpx@public.gmane.org




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Thanks guys, number_with_precision does the job for me.


On Oct 5, 4:18 am, Rob Biedenharn
<R...-xa9cJyRlE0mWcWVYNo9pwxS2lgjeYSpx@public.gmane.org>
wrote:
> On Oct 4, 2007, at 2:22 PM, Stan Kaufman wrote:
>
>
>
>
>
> > On Oct 4, 6:52 am, Rob Biedenharn
<R...-xa9cJyRlE0mWcWVYNo9pwxS2lgjeYSpx@public.gmane.org> wrote:
>
> >> Of course you can, it''s just Ruby.  If you want to stay
with a Rails
> >> solution, try number_with_precision(136.5325325, 2)
> >> (and then look at the source for that method and you
won''t need the
> >> method anymore)
>
> > number_with_precision doesn''t round correctly, though. From
the
> > source:
>
> >       # Formats a +number+ with the specified level of +precision+
> > (e.g., 112.32 has a precision of 2). The default
> >       # level of precision is 3.
> >       #
> >       # ==== Examples
> >       #  number_with_precision(111.2345)     # => 111.235
> >       #  number_with_precision(111.2345, 2)  # => 111.24
> >       #  number_with_precision(13, 5)        # => 13.00000
> >       #  number_with_precision(389.32314, 0) # => 389
> >       def number_with_precision(number, precision=3)
> >         "%01.#{precision}f" % number
> >       rescue
> >         number
> >       end
>
> > 111.2345 to two decimal places should be 111.23, not 111.24.
>
> The doc is wrong -- probably written by a human ;-)
>
> $ script/console
> Loading development environment.
>  >> helper.number_with_precision(111.2345, 2)
> => "111.23"
>
> I suspect the aforementioned human applied the precision=2 to the
> result of the precision=3 shown just above it rather than the
> original 111.2345 argument.
>
> -Rob
>
> Rob Biedenharn          http://agileconsultingllc.com
> R...-xa9cJyRlE0mWcWVYNo9pwxS2lgjeYSpx@public.gmane.org

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