Here is my solution.
falses <- which(!x)
first.false <- head(falses, 1)
last.false <- tail(falses, 1)
which(x[first.false:last.false]) + first.false - 1
Best regards,
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and
Forest
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
Kliniekstraat 25
1070 Anderlecht
Belgium
+ 32 2 525 02 51
+ 32 54 43 61 85
thierry.onkel...@inbo.be
www.inbo.be
To call in the statistician after the experiment is done may be no more than
asking him to perform a post-mortem examination: he may be able to say what the
experiment died of. ~ Sir Ronald Aylmer Fisher
The plural of anecdote is not data. ~ Roger Brinner
The combination of some data and an aching desire for an answer does not ensure
that a reasonable answer can be extracted from a given body of data. ~ John
Tukey
________________________________________
Van: r-help-boun...@r-project.org [r-help-boun...@r-project.org] namens Fisher
Dennis [fis...@plessthan.com]
Verzonden: vrijdag 6 juni 2014 23:45
Aan: r-h...@stat.math.ethz.ch
Onderwerp: [R] Identifying one or more TRUE in the middle of an array
R 3.1.0
OS X
Colleagues
I have an array (I am using T/F rather than TRUE/FALSE for convenience) that
could have patterns like:
c(T, T, T, F, F, F, T, F, T, T, T) ## T at either end, a
single T in the middle
c(F, F, F, F, F, T, F, F, T, T, T) ## T at the tail end, a
single T in the middle
c(T, T, T, F, F, T, T, F, F, F, F) ## T at the front end,
two T in the middle
c(T, T, T, F, F, T, T, F, T, F, F) ## T at the front end,
three T in the middle (not contiguous)
c(F, F, F, F, F, T, F, F, F, F, F) ## no T at either end,
a single T in the middle
There might (or might not) be one or more T at the beginning (or the end).
There might or might not be one or more T in the middle (not in a series that
continues to either end) and the position of these T values varies.
I am trying to identify the indices (if any) of these T values in the middle
A brute force approach would be to strip off any contiguous T values from each
end, then look for any remaining T values. Can anyone propose a more clever
approach?
Dennis
Dennis Fisher MD
P < (The "P Less Than" Company)
Phone: 1-866-PLessThan (1-866-753-7784)
Fax: 1-866-PLessThan (1-866-753-7784)
www.PLessThan.com
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