Lorenzo Isella <lorenzo.isella <at> gmail.com> writes: > > Dear All, > I am given a time series such at, at every time t_i, I am given a set > of data (every element of the set is just an integer number). > What I need is an injective function able to map every set into a > number (possibly an integer number, but that is not engraved in the > stone). Does anybody know how to achieve that?
In set theory you learn about the function that assigns to a set of integers (i1, ..., in) the integer p1^i1 * ... * pn^in, where p1, ... is the sequence of primes. In practice, unfortunately, this will lead to too large numbers. I would recommend the 'digest' package that provides hashing functions such as 'md5', etc., thanks to Dirk Eddelbuettel. It is injective enough and returns character strings of fixed length. Hans Werner > Cheers > > Lorenzo > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
