Alright, I feel like an absolute idiot, but the question is simple, and 30
minutes of looking hasn't yet yeilded the answer.
I want to take a float (say 0.0) and output it with a space in front if it's
positive, - in front if it's negative, and be able to specify how many
numbers after the decimal get printed (padding with zeros). This will be
used to output currency, and I just know there's a simple way to do it with
Ruby, but not finding it. 
Sorry to bother you all.
printf "% .2f", 3.14159
3.14
printf "% .2f", -2
-2.00
best regards,
Ed
On Tue, Sep 13, 2005 at 12:25:28PM +0900, Kevin Brown wrote:
I want to take a float (say 0.0) and output it with a space in front if it's
positive, - in front if it's negative, and be able to specify how many
numbers after the decimal get printed (padding with zeros).
=> [" 123.46", "-123.46"]
You can also use printf with the same format for direct output.
Kind regards
robert
Kevin Brown <blargity@gmail.com> wrote:
Alright, I feel like an absolute idiot, but the question is simple,
and 30 minutes of looking hasn't yet yeilded the answer.I want to take a float (say 0.0) and output it with a space in front
if it's positive, - in front if it's negative, and be able to specify
how many numbers after the decimal get printed (padding with zeros). This will be used to output currency, and I just know there's a
simple way to do it with Ruby, but not finding it.Sorry to bother you all.
[123.456,-123.456].map{|f| sprintf "% 3.2f", f}
Or you can use the % operator on a string which I like better. I.e.
"%3.2f" % 1.0 #=> " 1.00"
regards,
Brian
On 13/09/05, Robert Klemme <bob.news@gmx.net> wrote:
Kevin Brown <blargity@gmail.com> wrote:
> Alright, I feel like an absolute idiot, but the question is simple,
> and 30 minutes of looking hasn't yet yeilded the answer.
>
> I want to take a float (say 0.0) and output it with a space in front
> if it's positive, - in front if it's negative, and be able to specify
> how many numbers after the decimal get printed (padding with zeros).
> This will be used to output currency, and I just know there's a
> simple way to do it with Ruby, but not finding it.
>
> Sorry to bother you all.>> [123.456,-123.456].map{|f| sprintf "% 3.2f", f}
=> [" 123.46", "-123.46"]You can also use printf with the same format for direct output.
Kind regards
robert
--
http://ruby.brian-schroeder.de/
Stringed instrument chords: http://chordlist.brian-schroeder.de/
Just remember that if you have multiple formatted pieces in the same string, you need to supply the argument to the #% method as an array:
m = 57.23562
s = 83.333333
"%3.2f - %3.2f = %3.2f" % [ m, s, m-s ]
#=> "57.24 - 83.33 = -26.10"
The fun comes when you use string interpolation along with sprintf's codes:
class Numeric
def rounded_to( decimals )
decimals = decimals.round
if decimals < 0
factor = 10.0 ** -decimals
( ( self / factor ).round * factor ).round.to_s
else
"%.#{decimals}f" % self
end
end
end
[ 1, -1, 0.017, -0.017, 1254, -81.2412234 ].each{ |number|
[5,2,1,0,-1,-2,-3].each{ |decimal_places|
puts number.rounded_to( decimal_places )
}
puts '-' * 40
}
1.00000
1.00
1.0
1
0
On Sep 13, 2005, at 7:22 AM, Brian Schr枚der wrote:
Or you can use the % operator on a string which I like better. I.e.
"%3.2f" % 1.0 #=> " 1.00"
----------------------------------------
-1.00000
-1.00
-1.0
-1
0
----------------------------------------
0.01700
0.02
0.0
0
----------------------------------------
-0.01700
-0.02
-0.0
-0
0
----------------------------------------
1254.00000
1254.00
1254.0
1254
1250
1300
1000
----------------------------------------
-81.24122
-81.24
-81.2
-81
-80
-100
0
----------------------------------------
How would I format a number to simply be left-zero-padded with 2 floating
points?
eg.
000.24 from .238888888
001.24 from 1.237777777
010.25 from 10.249999999
100.25 from 100.24999999
I can do: %.2f to get the 2 decimals, but it doesn't do left-zero-pad.
I can do: %03d to pad 3 digits to the left, but it doesn't trim the decimals
I can do: printf("%03d%.2f", val, (val.to_f-val.to_i)) but that always
injects
an extra 0 like so:
0000.24
0010.24
0100.25
1000.25
I have yet to find a good (useful) doc on how the format args work, so point
me there but beware that most of the docs out there are super useless 
-henry
On 9/13/05, Gavin Kistner <gavin@refinery.com> wrote:
On Sep 13, 2005, at 7:22 AM, Brian Schr枚der wrote:
> Or you can use the % operator on a string which I like better. I.e.
> "%3.2f" % 1.0 #=> " 1.00"Just remember that if you have multiple formatted pieces in the same
string, you need to supply the argument to the #% method as an array:m = 57.23562
s = 83.333333
"%3.2f - %3.2f = %3.2f" % [ m, s, m-s ]#=> "57.24 - 83.33 = -26.10"
The fun comes when you use string interpolation along with sprintf's
codes:class Numeric
def rounded_to( decimals )
decimals = decimals.round
if decimals < 0
factor = 10.0 ** -decimals
( ( self / factor ).round * factor ).round.to_s
else
"%.#{decimals}f" % self
end
end
end[ 1, -1, 0.017, -0.017, 1254, -81.2412234 ].each{ |number|
[5,2,1,0,-1,-2,-3].each{ |decimal_places|
puts number.rounded_to( decimal_places )
}
puts '-' * 40
}1.00000
1.00
1.0
1
0
0
0
----------------------------------------
-1.00000
-1.00
-1.0
-1
0
0
0
----------------------------------------
0.01700
0.02
0.0
0
0
0
0
----------------------------------------
-0.01700
-0.02
-0.0
-0
0
0
0
----------------------------------------
1254.00000
1254.00
1254.0
1254
1250
1300
1000
----------------------------------------
-81.24122
-81.24
-81.2
-81
-80
-100
0
----------------------------------------
--
john hager
-------------------------------------
netcam@gmail.com
url: http://www.orgo.com
cell: 619.261.5990
How would I format a number to simply be left-zero-padded with 2 floating
points?eg.
000.24 from .238888888
001.24 from 1.237777777
010.25 from 10.249999999
100.25 from 100.24999999I can do: %.2f to get the 2 decimals, but it doesn't do left-zero-pad.
I can do: %03d to pad 3 digits to the left, but it doesn't trim the decimals
"%06.2f"
I can do: printf("%03d%.2f", val, (val.to_f-val.to_i)) but that always
injects
an extra 0 like so:0000.24
0010.24
0100.25
1000.25
"%07.2f"
I have yet to find a good (useful) doc on how the format args work, so point
me there but beware that most of the docs out there are super useless
printf(3) completely explains format strings.
On Nov 15, 2005, at 4:14 PM, hmmm wrote:
--
Eric Hodel - drbrain@segment7.net - http://segment7.net
FEC2 57F1 D465 EB15 5D6E 7C11 332A 551C 796C 9F04
hmmm <netcam@gmail.com> writes:
How would I format a number to simply be left-zero-padded with 2 floating
points?eg.
000.24 from .238888888
001.24 from 1.237777777
010.25 from 10.249999999
100.25 from 100.24999999I can do: %.2f to get the 2 decimals, but it doesn't do left-zero-pad.
I can do: %03d to pad 3 digits to the left, but it doesn't trim the decimalsI can do: printf("%03d%.2f", val, (val.to_f-val.to_i)) but that always
injects
an extra 0 like so:0000.24
0010.24
0100.25
1000.25I have yet to find a good (useful) doc on how the format args work, so point
me there but beware that most of the docs out there are super useless
Try this: printf("%07.2f", val)
The "7" is the total field width, including the decimal point. The "2"
represents the number of decimal places. The leading "0" means to
zero-pad.
--
Lloyd Zusman
ljz@asfast.com
God bless you.