[R] alignment algorithm or pattern frequency calculation

[Nordlund, Dan (DSHS/RDA)]

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Weiwei Shi
> Sent: Thursday, October 18, 2007 3:32 PM
> To: jim holtman
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] alignment algorithm or pattern frequency calculation
> 
> for example,
> 
> a,b: 3 which means a and b appear together 3 times in my input list.
> 
> On 10/18/07, jim holtman <jholtman at gmail.com> wrote:
> > It would be helpful if you explained what the numbers mean.
> >
> > On 10/18/07, Weiwei Shi <helprhelp at gmail.com> wrote:
> > > Hi,
> > >
> > > I am looking for an algorithm (better if it is 
> implemented in R) which
> > > can do the following:
> > >
> > > from the following list:
> > > a,b,c,d
> > > a,b,c
> > > b,c
> > > a,b,c,d,e
> > >
> > > to calculate
> > > a,b,c,d: 2
> > > a,b,c: 3
> > > a,b: 3
> > > a,c: 3
> > > b,c: 4
> > > b,c,d:2
> > >
> > > here, the order is not important.
> > >
> > > Thanks.
> > >

I guess I have more questions than answers.
1. What are the rules for deciding on which patterns to search for? You don't list c,d or c,d,e, or single character patterns.
2. Are these patterns stored in comma separated strings or as character vectors or...?

Dan

Daniel J. Nordlund
Research and Data Analysis
Washington State Department of Social and Health Services
Olympia, WA  98504-5204