Sort of a quick question. I'm writing:
puts "%.3f %.4f %.5f" % [3.998877, 3.998877, 3.998877]
and get the following output:
3.999 3.9989 3.99888
sprintf simply rounds the numbers. How do I restrict that rounding?
views:
1665answers:
4
+1
A:
you will probably need to truncate the numbers to the accuracy that you want.
f = 3.1919183
puts (f * 1000).truncate() / 1000
CookieOfFortune
2009-10-02 22:02:57
sorry? could you give an example?
gmile
2009-10-02 22:03:49
I'm not sure what you mean by "restrict the rounding". Specifically, what result are you looking for in your above example?
Jeff Godfrey
2009-10-02 22:07:55
I just want my numbers 'as is': 3.998 3.9988 3.99887
gmile
2009-10-02 22:09:59
so that would be truncation.
rampion
2009-10-02 22:39:10
A:
To get the numbers 'as is', you should store them as strings. As soon as you represent them as floats you lose information about the amount of built-in precision.
Peter
2009-10-03 00:35:42
+1
A:
>> def truncN f, digits
>> t = 10.0 ** digits
>> "%.#{digits}f" % ((f * t).truncate / t)
>> end
=> nil
>> n
=> 1.11181111
>> "%.3f" % n
=> "1.112"
>> truncN n, 3
=> "1.111"
DigitalRoss
2009-10-03 03:39:55
+1
A:
>> 3.998877.to_s[/^\d+\.\d{3}/].to_f
=> 3.998
>> 3.998877.to_s[/^\d+\.\d{4}/].to_f
=> 3.9988