There's also the `cheat sheet' http://cran.r-project.org/doc/contrib/R-and-octave-2.txt that might be useful for Matlab speakers.
Andy > From: Dimitris Rizopoulos > > Hi Bryan, > > 1. which(x==1) > 2. X[2:nrow(X),] or X[,2:ncol(X)] > > The "An Introduction to R" document is very usdeful for this kind of > things. > > I hope it helps. > > Best, > Dimitris > > ---- > Dimitris Rizopoulos > Ph.D. Student > Biostatistical Centre > School of Public Health > Catholic University of Leuven > > Address: Kapucijnenvoer 35, Leuven, Belgium > Tel: +32/16/396887 > Fax: +32/16/337015 > Web: http://www.med.kuleuven.ac.be/biostat/ > http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm > > > ----- Original Message ----- > From: "Bryan L. Brown" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Thursday, October 07, 2004 4:10 PM > Subject: [R] Equivalents of Matlab's 'find' and 'end' > > > > Sorry if these questions have been asked recently--I'm new to this > > list. > > > > I'm primarily a Matlab user who is attempting to learn R and I'm > > searching for possible equivalents of commands that I found very > > handy in Matlab. So that I don't seem ungrateful to those who may > > answer, I HAVE determined ways to carry out these processes in > > 'brute force' sorts of ways in R code, but they lack the elegance > > and simplicity of the Matlab commands. Also, if you know that no > > such commands exist, that bit of knowledge would be helpful to know > > so that I don't continue fruitless searches. > > > > The first is Matlab's 'find' command. > > This is one of the most useful commands in Matab. Basically, if X > > is the vector > > > > X=[3, 2, 1, 1, 2, 3] > > > > the command > > > > 'find(X==1)' > > > > would return the vector [3, 4] which would indicate that the vector > > X had the value of 1 at the 3 and 4 positions. This was an > > extremely useful command for subsetting in Matlab. The closest > > thing I've found in R has been 'match' but match only returns the > > first value as opposed to the position of all matching values. > > > > The second Matlab command that I'd like to find an R equivalent for > > is 'end'. 'end' is just a simple little command that indicates the > > end of a row/column. It is incredibly handy when used to subset > > matrices like > > > > Y = X(2:end) > > > > and produces Y=[2, 1, 1, 2, 3] if the X is the same as in the > > previous example. This cutsie little command was extremely useful > > for composing programs that were flexible and could use input > > matrices of any size without modifying the code. I realize > that you > > can accomplish the same by Y <- X[2:length(X)] in R, but > this method > > is ungainly, particularly when subsetting matrices rather than > > vectors. > > > > If anyone has advice, I'd be grateful, > > > > Bryan L. Brown > > Integrative Biology > > University of Texas at Austin > > Austin, TX 78712 > > 512-965-0678 > > [EMAIL PROTECTED] > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > [EMAIL PROTECTED] mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide! > > http://www.R-project.org/posting-guide.html > > > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > > ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html