I have a number that is of type float. I want to format it as dollars
and cents. How do you recommend I do it? 
···
--
John Kopanas
john@kopanas.com
http://www.kopanas.com
http://www.cusec.net
http://www.soen.info
never, never, never use floats to represent money.
-a
···
On Thu, 23 Nov 2006, John Kopanas wrote:
I have a number that is of type float. I want to format it as dollars
and cents. How do you recommend I do it?
--
my religion is very simple. my religion is kindness. -- the dalai lama
John Kopanas wrote:
I have a number that is of type float. I want to format it as dollars
and cents. How do you recommend I do it?
An example wouldn't hurt for the non-american *cough* minority.
Is "$%.2f".format(moniez) what you need?
David Vallner
"John Kopanas" <kopanas@gmail.com> writes:
I have a number that is of type float. I want to format it as dollars
and cents. How do you recommend I do it?
format("$%.2f",3.3)
···
--
David Kastrup, Kriemhildstr. 15, 44793 Bochum
John Kopanas wrote:
I have a number that is of type float. I want to format it as dollars
and cents. How do you recommend I do it?
Do you want delimiters between each group of three digits? As in:
$123,456,789.33 # US style
$123.456.789,33 # European style
If not, the replies you have gotten show how to get two decimal places after
the decimal point.
···
--
Paul Lutus
http://www.arachnoid.com
John Kopanas wrote:
I have a number that is of type float. I want to format it as dollars
and cents. How do you recommend I do it?
Here's my shot at it:
class Numeric
def to_currency( pre_symbol='$', thousands=',', decimal='.',
post_symbol=nil )
"#{pre_symbol}#{
( "%.2f" % self ).gsub(
/(\d)(?=(?:\d{3})+(?:$|\.))/,
"\\1#{thousands}"
)
}#{post_symbol}"
end
end
[
1,21,321,4321,54321,654321,7654321,87654321,
1.5,21.5,321.5,4321.5,54321.5,654321.5,
].each{ |n|
puts "%14s -> %s" % [ n.to_s, n.to_currency ]
puts "%14s -> %s" % [ (-n).to_s, (-n).to_currency ]
}
#=> 1 -> $1.00
#=> -1 -> $-1.00
#=> 21 -> $21.00
#=> -21 -> $-21.00
#=> 321 -> $321.00
#=> -321 -> $-321.00
#=> 4321 -> $4,321.00
#=> -4321 -> $-4,321.00
#=> 54321 -> $54,321.00
#=> -54321 -> $-54,321.00
#=> 654321 -> $654,321.00
#=> -654321 -> $-654,321.00
#=> 7654321 -> $7,654,321.00
#=> -7654321 -> $-7,654,321.00
#=> 87654321 -> $87,654,321.00
#=> -87654321 -> $-87,654,321.00
#=> 1.5 -> $1.50
#=> -1.5 -> $-1.50
#=> 21.5 -> $21.50
#=> -21.5 -> $-21.50
#=> 321.5 -> $321.50
#=> -321.5 -> $-321.50
#=> 4321.5 -> $4,321.50
#=> -4321.5 -> $-4,321.50
#=> 54321.5 -> $54,321.50
#=> -54321.5 -> $-54,321.50
#=> 654321.5 -> $654,321.50
#=> -654321.5 -> $-654,321.50
*Especially* when the language has "BigDecimal" built in. 
However ... be aware that if you need to deal with compound interest calculations, they are difficult to do in most decimal arithmetic implementations, so at that point, you often need to bite the floating point (and exponential/logarithm) bullet. That's why HP still makes the 12C and still sells it by the carload today -- it does everything exactly the way people expect it to be done.
Also, see the other thread about just how badly Excel and VBA do this sort of thing.
···
ara.t.howard@noaa.gov wrote:
On Thu, 23 Nov 2006, John Kopanas wrote:
I have a number that is of type float. I want to format it as dollars
and cents. How do you recommend I do it?never, never, never use floats to represent money.
Fixed-point arithmetic - Wikipedia
-a
--
M. Edward (Ed) Borasky, FBG, AB, PTA, PGS, MS, MNLP, NST, ACMC(P)
http://borasky-research.blogspot.com/
If God had meant for carrots to be eaten cooked, He would have given rabbits fire.
ahhh... yes... now how do we take it up a notch and divide thousand
from hundreds... for example:
$10,343 or better yet $1,234,234.32
?
···
On 11/24/06, David Kastrup <dak@gnu.org> wrote:
"John Kopanas" <kopanas@gmail.com> writes:
> I have a number that is of type float. I want to format it as dollars
> and cents. How do you recommend I do it?format("$%.2f",3.3)
--
David Kastrup, Kriemhildstr. 15, 44793 Bochum
--
John Kopanas
john@kopanas.com
http://www.kopanas.com
http://www.cusec.net
http://www.soen.info
I'm very happy someone said that. But to expand on at least one reason
why:
In many countries the taxman will be very unhappy, as things like
VAT/sales tax often have _very_ specific rules about how rounding and
fractions should be handled (i.e. UK regulations specify two
alternative methods that it's your responsibility to ensure your
results matches to the penny if you generate VAT invoices).
Vidar
···
ara.t.howard@noaa.gov wrote:
On Thu, 23 Nov 2006, John Kopanas wrote:
> I have a number that is of type float. I want to format it as dollars
> and cents. How do you recommend I do it?never, never, never use floats to represent money.
Phrogz wrote:
John Kopanas wrote:
> I have a number that is of type float. I want to format it as dollars
> and cents. How do you recommend I do it?Here's my shot at it:
class Numeric
def to_currency( pre_symbol='$', thousands=',', decimal='.',
post_symbol=nil )
"#{pre_symbol}#{
( "%.2f" % self ).gsub(
/(\d)(?=(?:\d{3})+(?:$|\.))/,
"\\1#{thousands}"
)
}#{post_symbol}"
end
end
Nice try. Now all it needs is to be able to handle other variations of
the number of digits between each separator, which may not be uniform
(i.e. 100,00,000.00), and it should be able to handle most
international formats.
Vidar
John Kopanas wrote:
ahhh... yes... now how do we take it up a notch and divide thousand
from hundreds... for example:$10,343 or better yet $1,234,234.32
This approach ignores a certain locale issue, but:
···
--------------------------------------
#!/usr/bin/ruby -w
class String
def currency_format()
while self.sub!(/(\d+)(\d\d\d)/,'\1,\2'); end
self
end
end
0.upto(20) do |n|
x = 10 ** n
xs = x.to_s + ".33"
puts xs.currency_format().rjust(30)
end
--------------------------------------
1.33
10.33
100.33
1,000.33
10,000.33
100,000.33
1,000,000.33
10,000,000.33
100,000,000.33
1,000,000,000.33
10,000,000,000.33
100,000,000,000.33
1,000,000,000,000.33
10,000,000,000,000.33
100,000,000,000,000.33
1,000,000,000,000,000.33
10,000,000,000,000,000.33
100,000,000,000,000,000.33
1,000,000,000,000,000,000.33
10,000,000,000,000,000,000.33
100,000,000,000,000,000,000.33
--
Paul Lutus
http://www.arachnoid.com
There's one of those on Rubyforge. Gavin Sinclair has an "extensions"
library to which I contributed my solution some time back.
-austin
···
On 11/25/06, Vidar Hokstad <vidar.hokstad@gmail.com> wrote:
Phrogz wrote:
> John Kopanas wrote:
> > I have a number that is of type float. I want to format it as dollars
> > and cents. How do you recommend I do it?
>
> Here's my shot at it:
>
> class Numeric
> def to_currency( pre_symbol='$', thousands=',', decimal='.',
> post_symbol=nil )
> "#{pre_symbol}#{
> ( "%.2f" % self ).gsub(
> /(\d)(?=(?:\d{3})+(?:$|\.))/,
> "\\1#{thousands}"
> )
> }#{post_symbol}"
> end
> endNice try. Now all it needs is to be able to handle other variations of
the number of digits between each separator, which may not be uniform
(i.e. 100,00,000.00), and it should be able to handle most
international formats.
--
Austin Ziegler * halostatue@gmail.com * http://www.halostatue.ca/
* austin@halostatue.ca * You are in a maze of twisty little passages, all alike. // halo • statue
* austin@zieglers.ca