i am trying to use the
sample command and have one question about it:
i am getting the error
Error in sample(length(x), size, replace, prob) :
insufficient positive probabilities
when i use something like:
sample (1:4, prob=c(0,0,1,0))[1]
i was expecting that to return a 3 every time
while this is not exactly what i am using it for, i need the capabilities to
deal with zeros (as the probability valuees that i will be using wil vary,
and sometimes will include zeros), and this seems like the zero's are the
problem...
currently i am assigning zero values in my initial probability vector to a
miniscule value(1E-4)
is there a more efficient way to deal with this, or another command that
does a similar thing to only select a single element, where as sample orders
the entire set according to the prob?
if it helps, i am using R 1.4.0 on win-me
thanks
jimi adams
Department of Sociology
The Ohio State University
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614-688-4261
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"jimi adams" <imij at columbus.rr.com> writes:> i am trying to use the > sample command and have one question about it: > i am getting the error > > Error in sample(length(x), size, replace, prob) : > insufficient positive probabilities > > when i use something like: > sample (1:4, prob=c(0,0,1,0))[1] > > i was expecting that to return a 3 every time > while this is not exactly what i am using it for, i need the capabilities to > deal with zeros (as the probability valuees that i will be using wil vary, > and sometimes will include zeros), and this seems like the zero's are the > problem... > > currently i am assigning zero values in my initial probability vector to a > miniscule value(1E-4) > > is there a more efficient way to deal with this, or another command that > does a similar thing to only select a single element, where as sample orders > the entire set according to the prob?sample (1:4, size=1, prob=c(0,0,1,0)) ===== The default is size=4 and subsetting the result doesn't change that. Notice that this is sampling without replacement, so what is the algorithm supposed to do when the first element has been sampled? -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
On Fri, 8 Mar 2002, jimi adams wrote:> i am trying to use the > sample command and have one question about it: > i am getting the error > > Error in sample(length(x), size, replace, prob) : > insufficient positive probabilities > > when i use something like: > sample (1:4, prob=c(0,0,1,0))[1] > > i was expecting that to return a 3 every timeIt sounds like you want to add replace=TRUE, eg R> sample(1:4,prob=c(0,0,1,0),replace=TRUE) [1] 3 3 3 3 You were trying to sample four numbers without replacement from a set effectively containing only one number. That's what the error message means. -thomas -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._