[R] stuff I used to do in Matlab

[Philippe Grosjean]

I am currently converting Matlab code into R code. All basic matrix
operations in Matlab exist also in R... You just have to find them because
functions names and logic are sometimes a little bit different. You have a
few hints with other answers in this thread. R is strongest in indexing
matrices. It handles also data.frames, factors, etc... with no direct
equivalent in Matlab. You are better to consider you learn a new language
instead of trying to use R as a Matlab-like language. If you do so, I guess
you will prefer R than Matlab for most applications (like I do!). My R code
tend also to be somewhat shorter than Matlab equivalent :-) However, Matlab
code (if run in v. 6) is often faster :-(
All the best,

Philippe Grosjean


...........]<(({?<...............<?}))><...............................
 ) ) ) ) )	 __               	 __
( ( ( ( ( 	|__)              	|  _
 ) ) ) ) )	|   hilippe       	|__)rosjean
( ( ( ( ( 	Marine Biol. Lab., ULB, Belgium
 ) ) ) ) )	                  	 __
( ( ( ( ( 	|\  /|            	|__)
 ) ) ) ) )	| \/ |ariculture &	|__)iostatistics
( ( ( ( (
 ) ) ) ) )	e-mail: phgrosje at ulb.ac.be or phgrosjean at sciviews.org
( ( ( ( ( 	SciViews project coordinator (http://www.sciviews.org)
 ) ) ) ) )      tel: 00-32-2-650.29.70 (lab), 00-32-2-673.31.33 (home)
( ( ( ( (
 ) ) ) ) )      "I'm 100% confident that p is between 0 and 1"
( ( ( ( (                                  L. Gonick & W. Smith (1993)
 ) ) ) ) )
.......................................................................


>Hi,
>	I'm new to R, and trying to map stuff I knew how to do in Matlab
>to R. For instances, in matlab, sum(x) gave the column sums of
>matrix(/vector) x. In R it just gives the sum of all the elements,
>regardless of their form (vector or matrix). Is there a simple way to
>return a vector of column sums for a matrix? Also, in Matlab binary
>operators exist for concatenating a matrix onto the end or the bottom of
>another matrix (i.e. horiz or vertically) but no such operators seem to
>exist for R. is there an easy way to concatenate matrices? (I have found a
>way which involves several steps, first creating a new matrix of zeros
>with dimensions based on the dims of the old ones, and then inserting the
>contents of the old matrices into the new one, but this seems very
>cumbersome, esp. since I'm used to being able to do it with something like
>c = [a,b]. Thanks for entertaining my newbie questions

>dave

>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>|David Richmond                It works on a          |
>+ Dept. of Sociology          complex scientific      +
>|Saint Mary's College          principle, known as    |
>+ Notre Dame, IN 46556               "pot luck."      +
>|219-284-4517                    - The Doctor         |
>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
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
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._