[vox-tech] [OT] Binary Representation Challenge

[Alex Mandel]

Micah J. Cowan wrote:
> On Tue, Sep 20, 2005 at 12:23:13PM -0700, Alex Mandel wrote:
> 
>>Micah J. Cowan wrote:
>>
>>>On Tue, Sep 20, 2005 at 12:02:26PM -0700, Alex Mandel wrote:
>>>
>>>
>>>>I realize this might be not be a challenge for some of you.
>>>>--
>>>>I need to make a list of all possible permutations given 9 options and 
>>>>that you can choose any number of options at once.
>>>>I've figured out using nCr statistics that this is 511 choices, but now 
>>>>I need to represent them in 2^9 binary code: 000000001, 000000010 etc
>>>>
>>>>Anyone got a quick way? I thought about writing a python code or 
>>>>something but then I got confused just thinking about the algorthim.
>>>>
>>>>Now the best would be if you had an idea that I could implement with my 
>>>>limited toolset: R, OpenOffice, Python, and I guess I could add a 
>>>>package to Cygwin if necessary.
>>>
>>>If all you need is the different permutations of two-choice options, all
>>>of which can be selected in any combination, then this is exactly the
>>>same as counting in binary.
>>>
>>>Or is it actually printing the representation of the binary that is
>>>posing a problem?
>>
>>Correct, I need to print a list to represent the choices.
>>It's going to be a lookup table in a database on the backside of a 
>>webpage that pulls up a static map of the options picked.
> 
> 
> Well; so perhaps you could have a nine-element array of strings naming
> the options, and iteratively test each bit on each counting iteration,
> printing out the string at the same index as the bit you are testing,
> followed by " = yes" or " = no", depending on your needs?

I get what your saying, lets just say I'm not that experienced at using 
arrays.

On an interesting note though, we figured out how to overlay tranparent 
gifs(by layering DIV tags) so we only need 10 images instead of 512 and 
now just have to write a short script to build the html dynamically 
instead of a lookup table.

Thanks for the ideas- Alex