On Fri, 31 Dec 2010, Paolo Rossi wrote:
Hi Everyone,
quick question before the end of the year.
I have soem indices to select data from a bigger sample. I want to select n
days before each index and n days after the index. Any clever way to do it.
For heavy duty applications involving intervals - many intervals, finding
overlapping intervals, set operations, et cetera, you may want to use the
IRanges package:
http://www.bioconductor.org/help/bioc-views/release/bioc/html/IRanges.html
A for loop would do but I wanted to know if there is a moreR-friendly way to
approach this
Example
# InitialIndices
i2 = (90, 190, 290)
Like this:
i2 <- c(90, 190, 290)
as.vector( IRanges( start= i2 - 5, end = i2 + 5 ) )
[1] 85 86 87 88 89 90 91 92 93 94 95 185 186 187 188 189 190 191 192
[20] 193 194 195 285 286 287 288 289 290 291 292 293 294 295
HTH,
Chuck
# Indices I want to end up with
i3 = c(85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 185, 186, 187, 188, 189,
190, 191, 192, 193, 194, 195
285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295)
# A way to get Final Indices
SampleWidth
i3 = c(i2)
for (j in seq(1, SampleWidth )) {
i3 = c(i3, i2 + j )
i3 = c(i3, i2 - j )
}
I tried to tackle this with seq and the apply families but got nowhere
Thanks and Happy New Year
Paolo
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Charles C. Berry Dept of Family/Preventive Medicine
cbe...@tajo.ucsd.edu UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
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