It's far more useful to send your explanation to the list than it is to send it just to me. I've taken the liberty of doing so.
But this does sound like a job for ecdf() - what did you do, and what went wrong? On Fri, Dec 23, 2011 at 12:23 PM, Steven Jones <sjone...@jhmi.edu> wrote: > Actually, what I am trying to do is very simple. I want to take a large > vector of data, about 1.5 million observations and return a corresponding > vector of percentiles, each corresponding to the elements of the original > data vector in a 1:1 correspondence. > > Original data vector: x<--(x1,x2,x3,...xn) > ^ ^ ^ > | | | > Derived percentile vector: p<--(p1,p2,p3,...pn) > > Where pn<--is the percentile value of xn determined from the rank in the data > vector x. > > Ideally, there is a function which could return a vector p from my original > data vector x. > > My understanding, which may be incorrect, is that quantile() function returns > the value of x for a specified percentile rank in a vector. > > Steve > > -----Original Message----- > From: Sarah Goslee [mailto:sarah.gos...@gmail.com] > Sent: Friday, December 23, 2011 12:11 PM > To: Steven Jones > Cc: r-help@r-project.org > Subject: Re: [R] data vector to corresonding percentile ranks > > I'm not sure I understand the question, but does quantile() do what you want? > > On Fri, Dec 23, 2011 at 10:28 AM, Steve Jones <sjone...@jhmi.edu> wrote: >> I have a problem where I need to calculate the corresponding cohort >> percentile ranks for each of several variables. >> >> Essentially, what I need is a function that will calculate the >> distribution-free percentiles from each variable's data vector, returning a >> corresponding vector of percentiles: >> >> e.g.: >> >> percentile.my.data<-/function/(my.data) >> >> >> I tried to make ecdf() perform this task but was unsuccessful. >> >> I'd be grateful for any help or advice... >> >> > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
