How do I format return this value?

Ruby
1

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.

2

On 20 juil. 2010, at 14:13, Chad W. 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.

3

On Tue, Jul 20, 2010 at 1:13 PM, Chad W. [email protected]
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