Hi,
This might be a very naive question but I looked through ruby:Float
documentation for a method which round off’s a float number to x decimal
places with no luck.
Please share if you know.
Regards,
Jatinder
Hi,
This might be a very naive question but I looked through ruby:Float
documentation for a method which round off’s a float number to x decimal
places with no luck.
Please share if you know.
Regards,
Jatinder
Hi,
This might be a very naive question but I looked through ruby:Float
documentation for a method which round off’s a float number to x decimal
places with no luck.Please share if you know.
It rather depends on which of the 14-or-so regulalrly used rounding
algorithms you need.
Float#round has an inbuilt bias toward zero and is therefore not a
useful unbiased rounding in many circumstances.
Martin
Martin C. wrote:
Float#round has an inbuilt bias toward zero and is therefore not a
useful unbiased rounding in many circumstances.Martin
Chekc out:
http://facets.rubyforge.org/api/core/index.html
Look for the round_* methods.
T.
Thanks you all for the solutions!
Regards,
Jatinder
On 10/13/06, Martin C. [email protected] wrote:
Float#round has an inbuilt bias toward zero and is therefore not a
useful unbiased rounding in many circumstances.
But, to answer your original question: if you want a number to three
decimal places:
Multiply by 10^n
Round()
Divide by 10^n
Martin
On 10/13/06, Jatinder S. [email protected] wrote:
Hi,
This might be a very naive question but I looked through ruby:Float
documentation for a method which round off’s a float number to x decimal
places with no luck.Please share if you know.
One way is sprintf:
sprintf “%.4f”, 0.7458745 #=> “0.7459”
Another is multiple, round, divide:
class Float
alias_method :round_orig, :round
def round(n=0)
(self * (10.0 ** n)).round_orig * (10.0 ** (-n))
end
end
0.7458745.round(4) # => 0.7459
That’s about what you can get in Ruby. It should suffice for most
programs.
Of course no Float-based method can give you correct decimal arithmetic
(with nearest even rounding etc.). You need a special package for that.
0.15.round(1) # => 0.2 correct
0.25.round(1) #=> 0.3 should be 0.2
sprintf “%.1f”, 0.15 #=> “0.1” should be 0.2
sprintf “%.1f”, 0.25 #=> “0.2” correct
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