Comparing very long numeric strings

[Dar Scott]

On Tuesday, March 16, 2004, at 03:10 PM, Jim Lyons wrote:

> I have a long string of 1s and 0s in a variable representing the 
> states of cells in a cellular automata simulation. There can be more 
> than ten thousand cells.
...
> Finally, I wondered if there could be a difference between numeric and 
> string comparison, so I tried changing the comparison above to:
>
>     if "z"&nextState = "z"&curState then StopCA
>
> Surprisingly (to me) this fixed the problem.

Yes, = (and 'is') will compare numeric it the data looks numeric (or is 
internally).  I think if it is compared numeric, then it will be 
compared as double floating point.  Your string of 1's and 0's will 
look like a large numeral with digits.  As is, it might compare only 
the first 15 or so characters.

It would be nice to have a comparison function/operator that is string 
oriented always and does not try to compare numerically.

Your method will work.  Another one is this:

     if length(&nextState)=length(&curState) and &nextState contains 
&curstate

If your states are always the same size, then you can get by with only 
'contains'.

Dar Scott