On 29/04/2008 11:39 AM, Kenn Konstabel wrote:
Suppose X is a long vector of integers (typically about 30000 elements). Is
there an efficient way to detect whether there are at least N consecutive
zeros in X, and if yes, where does this occur?
for example, suppose X is:
...
and N is 10. I would like a foo(X, 10) to return something like c(6,19)
(start and end positions in X of at least 10 consecutive zeros). I can think
of a number of slow and probably inefficient ways of doing it (nested
loops..), but perhaps someone has a better idea..
Something based on rle() should be fairly easy. rle(x)$lengths > 9
identifies the long runs, cumsum(rle(x)$lengths) identifies where runs end.
Duncan Murdoch
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