1. RE: A sequence, by any other name
- Posted by Al Getz <Xaxo at aol.com> Feb 27, 2001
- 397 views
Hi Jonas, Jonas Temple wrote: > Hello all, > > What I need is a sure-fire way to determine in my program if a sequence > is a character sequence versus a sequence of numbers. I need to > determine this dynamically. > > Maybe this is a basic question? I dunno. > > Jonas > > Offhand there are two ways i can think of to do this. In general, for any arbitrary sequence there is no way to distinguish a character from a number that is stored in it. For example: n={65} --these are both exactly n={'A'} --the same sequence. One way to distinguish between the two is to store a second number along with the original value that tells your program which type had been stored such as: n={1,65} --a number n={0,'A'} --a character This is probably the easiest way to emulate a user defined type. When you go to use the data, your program first checks the first element of the sub sequence to determine what kind of data is stored there and acts accordingly. There is a second method which involves adding the number 256 to any positive integers in order to distinguish between characters and integers but it involves alot more testing on the number before you know what it is. If your interested i'll post that method next time. One good point about it is that it doesnt require any more space to store numbers like the first method does, which could be a big benefit for large data. Also keep in mind any kind of home made types are going to slow the code down somewhat. Good luck with it. --Al