Using round() in a SketchUp plugin

[steve r]

Hi, I'm new here (and pretty new to Ruby, as well as plugin creation) so if this is in a horribly wrong place let me know and I'll re-post.

In any case, I've got the following code in my plugin, and it's just not working.

percent = 100*array[0]
percent = percent.round(2)

I believe it should work, as this is the syntax I saw here , but SketchUp doesn't seem to recognize it. I'm just looking to take an unwieldy float value out of an array and tidy it up to two decimal places before putting it into a messagebox.

Thanks!

[TIG]

You haven't provided the whole picture.
Let's assume that ' array' is an array of numbers.
You need to pass a 'float' to '.round' so try using 100.0 instead of the 'integer' 100 - that will then force the answer into a float even when array[0] is an integer...

[Jim]

Hi Steve,

The Ruby version (1.8.6) which comes with SketchUp does not support the argument to round. This came in a later Ruby version. 1.8.7 I think.

Anyway, you can access the 1.8.6 docs from the same site: http://www.ruby-doc.org/core-1.8.6/index.html

[TIG]

To add a round 'range' etc to the current version of SUp's Ruby copy/paste this into a float_extras.rb file in Plugins to add these additional methods

class Float
  def round_to(x)
    (self*10**x).round.to_f/10**x
  end
  def ceil_to(x)
    (self*10**x).ceil.to_f/10**x
  end
  def floor_to(x)
    (self*10**x).floor.to_f/10**x
  end
end
=begin
Example usage;
num = 138.249
num.round_to(2)
# => 138.25
num.floor_to(2)
# => 138.24
num.round_to(-1)
# => 140.0
=end

replace .round with .round_to(n)
etc...

[steve r]

@jim said:

Hi Steve,

The Ruby version (1.8.6) which comes with SketchUp does not support the argument to round. This came in a later Ruby version. 1.8.7 I think.

Anyway, you can access the 1.8.6 docs from the same site: http://www.ruby-doc.org/core-1.8.6/index.html

That's a shame. In any case, I came up with a workaround, I suppose it's pretty obvious but I thought it might help anyone else who needs to do some rounding in SU:

percent = (10000*array[0]).to_i
percent = percent.to_f/100

Just add equal numbers of zeroes to the numbers if you want greater precision. As it's written, it rounds to two decimal places.

[Dan Rathbun]

There is also a backport ruby gem.. that "updates" older Ruby versions with features from newer releases.

But the weird thing is that then RUBY_VERSION and RUBY_PATCHLEVEL become meaningless.

[Dan Rathbun]

TIG's example WILL work, but requires that EVRYONE have that "extension".

You might put those methods inside a library module, inside your toplevel "author" module.

[steve r]

@dan rathbun said:

TIG's example WILL work, but requires that EVRYONE have that "extension".

You might put those methods inside a library module, inside your toplevel "author" module.

Well, does my simplified attempt at rounding above work? I only need to use it one time, so I would think it'd be faster just to do it via my method.

[Dan Rathbun]

@steve r said:

Well, does my simplified attempt at rounding above work?

No the round() function actually rounds.. the to_i() function actually truncates.

Use the "meat" of TIG's example in a single statement
.. or write methods into your module thus:

module Author; module ThisPlugin; end; end

module Author;;ThisPlugin

  class << self  # proxy class

    private # just to show that percent() will be private

    def percent( num )
      (num*10**-2)
    end

    public # just to show how to return to the default
           # of making following methods public.

    def round_number( num, places=0 )
      (num*10**places).round.to_f/10**places
    end

  end # proxy class

  begin
    num = 78.67812 # just for example
    per = percent( round_number(num,2) )
  end

end # module

[steve r]

@dan rathbun said:

No the round() function actually rounds.. the to_i() function actually truncates.

Use the "meat" of TIG's example in a single statement
.. or write methods into your module thus...

Good point! I hadn't considered that my method just truncates. I'll have to see if I can figure out a simple way to incorporate TIG's example into one statement; a lot of that code goes right over my head! Thanks for the help!