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From: Chad Weier on 20 Jul 2010 08:13
I have a method which calculates values and creates and object in a
class

Acalculation.new(valuea, valueb)

they go to

def to_s
"#{@valuea}#{@valueb}"
end

If valuea is 100 and valueb is 555555.5555

What would be the neatest and cleanest way to convert them to a
formatted value like this (note the rounding also)

valuea - 100.00 valueb - 555,555.56

I've found lots of code that does bit and pieces like I need but not
anything that does commas and rounding to 2 decimal places.
--
Posted via http://www.ruby-forum.com/.

From: Luc Heinrich on 20 Jul 2010 08:48
On 20 juil. 2010, at 14:13, Chad Weier wrote:

> valuea - 100.00 valueb - 555,555.56

"valuea - %.2f valueb - %.2f" % [valuea, valueb]

This returns

"valuea - 100.00 valueb - 555555.56"

Extra steps need to be taken for the thousands separator, I don't think Ruby has anything built-in for that.

--
Luc Heinrich - luc(a)honk-honk.com


From: Colin Bartlett on 20 Jul 2010 10:31
[Note: parts of this message were removed to make it a legal post.]

On Tue, Jul 20, 2010 at 1:13 PM, Chad Weier <emily.ward89(a)gmail.com> wrote:

> ...

What would be the neatest and cleanest way to convert them to a
> formatted value like this (note the rounding also)
> valuea - 100.00 valueb - 555,555.56
> I've found lots of code that does bit and pieces like I need but not
> anything that does commas and rounding to 2 decimal places.

The following methods (for Integers and Floats) are cut down versions of
some more general number formatting methods I wrote for myself some time
ago. No guarantees that they do what you want, but some quick tests seem to
show they do.

class Integer
# Puts digit separators for each group of 3 digits,
# with option to use a separator which is not an underscore.
def to_s!( grp_sep = '_' )
s = self.to_s
if grp_sep then
n = s.length
ne = ( if self < 0 then 1 else 0 end )
while (n -= 3) > ne do; s[ n, 0 ] = grp_sep; end
end
s
end
end

class Float
# Puts integer part digit separators for each group of 3 digits,
# with option to use a separator which is not an underscore.
# (if "." is used as the digits separator then the "decimal separator"
# will be changed from "." to ",");
def to_s!( n_dec_places, grp_sep = '_' )
unless n_dec_places.kind_of?( Integer ) then
raise "Float#to_s! - number of decimal places must be an integer"
end
unless n_dec_places >= 0 then
raise "Float#to_s! - negative number of decimal places yet to be
implemented to give robust results"
end
fmt_str = "%.#{n_dec_places}f"
s = sprintf( fmt_str, self )
if grp_sep then
n = s.rindex( '.' ) # if n_dec_places == 0 then n = nil
s[n, 1] = ',' if n && grp_sep == '.'
n ||= s.length
ne = ( if self < 0 then 1 else 0 end )
while (n -= 3) > ne do; s[ n, 0 ] = grp_sep; end
end
s
end
end

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