similar to: solving equations symbolically

Hello again. Now I have the following: > xx [1] "Solve(1 - R/100==(2*y)/10000,R)" > yacas(xx) expression(list(R == 100 * (1 - 2 * y/10000))) > I would like to put in a value for y and obtain R. I've tried more stuff with eval and Eval, but no luck yet. Any suggestions would be much appreciated. Thanks, Erin -- Erin Hodgess Associate Professor Department of Computer

Hello yet again, R People: I was working with Ryacas and yacas last night and all was well. Now this morning, I keep getting the following: > a <- Sym("a") > a Error in summary.connection(x) : invalid connection > When I go to yacas from the command line, it works fine. Any suggestions, please? I'm thinking that a port might be open, but here I have: >

Dear R people: Is there a way to perform simple polynomial multiplication; that is, something like (x - 3) * (x + 3) = x^2 - 9, please? I looked in poly and polyroot and expression. There used to be a package that had this, maybe? thanks, Erin -- Erin Hodgess Associate Professor Department of Computer and Mathematical Sciences University of Houston - Downtown mailto: erinm.hodgess at

Hi R People: Is there a package for automatic differentiation, please? thanks in advance, Erin -- Erin Hodgess Associate Professor Department of Computer and Mathematical Sciences University of Houston - Downtown mailto: erinm.hodgess at gmail.com

Dear R People: I have a monthly time series which runs from January 1998 to December 2010. When I use tsp I get the following: > tsp(ibm$ts) [1] 1998.000 2010.917 12.000 Is there an easy way to convert this to a seq.Date object, please? I would like to have something to the effect of 1998/01/01 .... 2010/12/01 Thanks, Erin -- Erin Hodgess Associate Professor Department of Computer

Hi, To my knowledge, Ryacas can do symbolic computation in R, like Mathematica or Maple. I wonder if it (or any other R package) can solve symbolically a system of equations? I have a system of four equations in four variables (non-linear, but not very hard to solve) and wonder if Ryacas or any other package can do it. I do not find the solution in Ryacas. Can it find a symbolic solution

Dear R People: I have a data frame, xm1, which has 12 rows and 4 columns. If I put is xm1[,-4], I get all rows, and columns 1 - 3, which is as it should be. Now, is there a way to use the names of the columns to omit them, please? Thanks so much in advance! Sincerely, Erin -- Erin Hodgess Associate Professor Department of Computer and Mathematical Sciences University of Houston - Downtown

Hi again. I'm putting together a little project with R, python, and a website. So I have an HTML file, a py file, an R file. Here is the HTML file: <form action="/cgi-bin/radio4.py" method="post" target="_blank"> <input type="radio" name="subject" value="Integrate" /> Integrate <input type="radio"

Everything is ok on Firefox, IE, and iPad. Thanks, Erin On Tue, Jan 8, 2013 at 7:58 PM, Erin Hodgess <erinm.hodgess at gmail.com> wrote: > Dear R People: > > Has anyone used R2HTML in web files that were on the Blackboard LMS, please? > > I'm starting to do these but wanted to know if there were any > potential pitfalls. > > Thanks, > Erin > > > --

Dear R People: Here is a goofy question: I want to extract the zip code from an address and here is my work so far: > add1 results.formatted_address "200 W Rosamond St, Houston, TX 77076, USA" > add1[1][32:36] <NA> <NA> <NA> <NA> <NA> NA NA NA NA NA > str(add1) Named chr "200 W Rosamond St, Houston, TX 77076,

Hello I would like to build R from source and use the PGI compiler, rather than the GCC compiler. I saw the instructions for the Intel compiler in the R Installation Manual, but I didn't see the PGI. I tried a few times without instructions, but without success. Any suggestions would be most welcome. Also, I hope this is the right group for the question. Sincerely, Erin -- Erin

Dear R People: I have generated the following table: > table(zza$DEATH,zza$GENDER) F M 2009-04-21 0 1 2009-04-22 4 2 2009-04-24 6 0 2009-04-25 1 3 2009-04-26 2 0 2009-04-28 3 0 2009-04-29 2 2 However, instead of total counts in the F and M columns, I would like percents. How would I do this, please? thanks, Erin -- Erin

Dear R People: When I want to produce a small sample confidence interval using t.test, I get the following: > t.test(buzz$var1, conf.level=.98)$conf.int [1] 2.239337 4.260663 attr(,"conf.level") [1] 0.98 How do I keep the attr statement from printing, please? I'm sure it's something really simple. Thanks, Sincerely, Erin -- Erin Hodgess Associate Professor Department

Dear R People: Here is a toy example: > x <- c("2E","5W","12H") > substr(x,2,2) [1] "E" "W" "2" > Sometimes x has 3 elements, sometimes 2. I want to extract the last element, and then extract the other 1 or 2 elements. How can I do this, please? TIA, Sincerely, Erin -- Erin Hodgess Associate Professor Department of

Dear R People: Here is something that I am sure is very simple. I'm just trying to re-create the C convolution example in the Extensions manual. Here is the subroutine: void convolve(double *a, int *na, double *b, int *nb, double *ab) { R_len_t i, j, nab = *na + *nb - 1; for(i = 0; i < nab; i++) ab[i] = 0.0; for(i = 0; i < *na; i++) for(j = 0; j < *nb; j++) ab[i + j] += a[i] *

Dear R Gurus: What is the name of the person who has all of the Tcl/tk stuff, please? I know it's James W, but can't remember his last name. I wanted to look at some of his examples. Thanks in advance! Sincerely, Erin -- Erin Hodgess Associate Professor Department of Computer and Mathematical Sciences University of Houston - Downtown mailto: erinm.hodgess at gmail.com

Thank you! On Thu, Aug 17, 2017 at 4:55 PM, Bert Gunter <bgunter.4567 at gmail.com> wrote: > r-package-devel is probably a better place to post this, especially if > you do not get a satisfactory reply here. This list is about R > programming, as you presumably know; your query is not. > > Cheers, > Bert > > > Bert Gunter > > "The trouble with having

Hello. I am creating a new RcmdrPlugin package. However, I am getting some very odd messages. R CMD build RcmdrPlugin.gstats_1.0.0 ERROR cannot change to directory ?RcmdrPlugin.gstats_1.0.0? es-macbook-air:~ emhodgess$ R CMD check RcmdrPlugin.gstats_1.0.0 Warning: ?RcmdrPlugin.gstats_1.0.0? is neither a file nor directory, skipping es-macbook-air:~ emhodgess$ cd RcmdrPlugin.gstats/

Dear R People: Suppose I have the following two character vectors: xf [1] "W" NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA > xg [1] NA "k" "h" NA "g" "r" "j" NA "v" "d" NA "v" NA "z" "r" "r" "i" > I want to end up with "W"

Dear R People: Is there a way to find which objects are functions via ls(), please? I'm sure that there is, but I'm not sure how. Thanks, Erin -- Erin Hodgess Associate Professor Department of Computer and Mathematical Sciences University of Houston - Downtown mailto: erinm.hodgess at gmail.com