Re: finding substrings

[David L Lorenz <lorenz@usgs.gov>]

Dave,
  This is probably best done by
using the ability of aggregateSeries to compute running statistics.  I
did not make this a generic function, but with some work, that could be
done.  Here's the concrete example:

  aggregateSeries(timeSeries(c(F,
F, F, T, T, F, F, T, T, F, F, T, T, T, F, F,
 F, F, F, T, T, T, F, F, T, T,
F, F, T, T, T), pos=1:31)
 ,moving=5,FUN=function(x) all(x
== c(F, F, T, T, F)))@data

  The idea is to create a timeSeries
object of relative time, do a moving computation of length = the length
of the test vector, and extract the data, which is a logical vector of
length 31 - 5 + 1 (in this case). The index numbers that you want can be
gotten by using which.
  Note that most everything can
be converted to a timeSeries object (numeric, logical, character, factor,
more?).
Dave

Dave Evens <devens8765@yahoo.com>
Sent by: s-news-owner@lists.biostat.wustl.edu

09/13/2005 04:23 AM

To	s-news@lists.biostat.wustl.edu
cc
Subject	[S] finding substrings

Dear all,

I would like to find the exact match of a
substring(/sub-vector) within a string (/vector). For
example, suppose I have

x <- c(F, F, F, T, T, F, F, T, T, F, F, T, T, T, F, F,
F, F, F, T, T, T, F, F, T, T, F, F, T, T, T)

y <- c(F, F, T, T, F)

What I would like to do is find the exact match of y
in x with possible overlapping, i.e. 

return back

2 6 23

I couldn't get it to work with matchList.

Thanks for any help in advance.

Dave




                
                 
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