similar to: using a variable in a subset of a dataframe

Dear Ms. R, I struggle with a very basic command for most of you: How to change the working-directory by command-line? Thank you! Georg. ****************** Georg Ehret Johns Hopkins University School of Medicine Broadway Research Building, Room 572 733 N. Broadway Baltimore, MD 21205 Phone: (410) 502-7530 Fax: (410) 502-7544 e-mail: georg@jhmi.edu [[alternative HTML version deleted]]

Dear R community, I am creating large graphs with hundreds of thousands of datapoints. My usual way for output was pdf, but now I am getting file sizes of >30Mb that do not open well (or at all) in Adobe. Is there a way to reduce the resolution or get rid of overlaying datapoints? Any other idea is also warmly welcome! Thank you and wishing you a good day! Georg. **********************

Dear R community, I am using densityplot (lattice package) for a large dataset and wish to print it to a jpeg (the pdf is huge). R crashes consistently. Am I doing it wrong or is densityplot incompatible with jpeg? I work on a Mac, R 2.7.0. > require(lattice) > jpeg("test.jpeg") > d[1:10] [1] 0.700218 0.700175 0.700357 0.700847 0.698286 0.701520 0.698158 0.699300 0.698819

Dear R community, I am using 6 variables to test for an effect (by linear regression). These 6 variables are strongly correlated among each other and I would like to find out the number of independent test that I perform in this calcuation. For this I calculated a matrix of correlation coefficients between the variables (see below). But to find the rank of the table in R is not the right

Dear R comunity, I am printing a number in a graph using "text(...)" - see code below: "fraction" is my number. I wish to print only two digits of the number and struggle to do this... options(digit=3) does not work... Thank you for your suggestions! Cheers, Georg. ********************************** Georg Ehret Johns Hopkins Baltimore

Dear R community, Can I please get some advice on the following: I wish to obtain a list of residuals, padded by NAs for NAs in my source data. I tried several options of "na.action", but did not succeed... Example: I would like to get "0,0,0,0,NA,NA": > a [1] 1 2 3 4 NA 9 > b [1] 3 4 5 6 7 NA > lm(a~b)$residuals 1 2 3 4 0 0 0 0 >

Dear R community, I have a dataframe with say 100 different variables. I wish to regress variable 1 separately on every other variable (2-100) in a linear regression using lm. There must be an easy way to do this without loops, but I have difficulties figuring this out... Can you please help? Thank you and best regards, Georg. ***************************************** Georg Ehret Johns Hopkins

Dear R community, I am using a dataframe with lots of NAs and wish to create subsets from that dataframe. In the example below I intend to create a subset with all entries with V1>1. To my surprise the result also contains all entries with V1=NA. I would wish to learn more why this is or what I do wrong. I know that I can use the command "subset" and the NAs will not appear, but

Dear R user group, I wish to plot small pie-charts to specific coordinates in a e.g. scatter-plot: E.g.: > plot(rnorm(100),rnorm(100)) > points(1,1,col="red",cex=4) -> I wish to put pie(c(2,3)) at the position of the red circle... How can I do this efficiently? Thanking you and wishing you a wonderful Sunday! Georg. ************************** Georg Ehret Johns Hopkins

Dear R community, I have a fairly large file with variables in rows. Every variable (thousands) needs to be regressed on a reference variable. The file is too big to load into R (or R gets too slow having done it) and I do now read in line by line with "scan" (see below) and write the results to out. Although improved, this is still very slow... Can someone please help me and suggest

Dear R community, I am plotting a histogram and would wish to display another variable of the same dataset in a very narrow heatmap just below the x-axis. Never mind the specifics of my task: How can I draw a second graph/image just below a first graph/image? Thank you! Georg. *************** Georg Ehret JHU Baltimore, MD 21043, USA [[alternative HTML version deleted]]

Dear R community, I have a scatterplot with multiple vertical ablines. I wish to color each interval between two ablines in a different color... Could you please indicate me how to do this efficiently? Thank you! Georg. ******************** Georg Ehret Johns Hopkins Baltimore [[alternative HTML version deleted]]

Dear R Usergroup, I have the following vector and I would like to split it on ",". How can I do this? > u [1] "160798191,160802762,160813395,160816017,160817873,160824082,160825247,160826925,160834272,160836257," Thank you in advance! With my best regards, Georg. ************************************ Georg Ehret Baltimore USA [[alternative HTML version deleted]]

Dear R communtiy, I do not understand why this does not work...: > betaS$SBP [1] 0.03274 -0.04216 -0.08986 -0.45980 0.60320 -0.63070 -0.05682 0.20130 > t<-c("betaS$SBP") > t [1] "betaS$SBP" > get(t) Error in get(t) : object 'betaS$SBP' not found [I am trying to use the variable "t" in a loop to call many different objects, but the

Dear R, I am writing a simple function to extract the sign of values and apply it to a data frame (see below). Whatever I do I get error-messages... What is wrong? Thanking you in advance, Cheers, Georg. *********************** Georg Ehret Institute of Genetic Medicine Johns Hopkins University Baltimore > extractsign<-function(x){ + if (x<0) a<--1 + else

Dear R community, I have data on beta&standard error (for the main effect of variable x), stratified by sex for my dataset. I wish to calculate the sex-interaction effect (as beta&se) from these two stratified datasets. Is there a package to do this? If not, any advice how to do it manually? Thank you very much and best regards, Georg. ************************ Georg Ehret, JHU,

Dear R community, I wish to ask a short question concerning factor-data in dataframes: When I subset the data and get rid of all data for one level, I still retain the level name (obtained by levels(dataframe$variablename) ). Is there a convenient way to get rid of the levels for which all data has been deleted? Thank you and wishing you an excellent day! Georg.

Dear R user group, I am working with boxplots and cannot solve the following problem: > data<-c(0,15,0,60,0,0,0,0,0,60,60,0,60,0,30,0) > data [1] 0 15 0 60 0 0 0 0 0 60 60 0 60 0 30 0 > boxplot(data) The boxplot has the first hinge and the mean-bar both at 0... Why is this the mean is clearly >0! Thanking you and wishing you an excellent day, Georg.

Dear R, I am often adding a total rows or column (sum over all rows or columns) when using table(data$1,data$2)... I do this now by adding the rows/columns and rbind() or cbind()... But there must be a more efficient way.... Could someone please give me a hint? Thank you! With my best regards, Georg. ******************* Georg Ehret Johns Hopkins Baltimore [[alternative HTML version deleted]]

Dear Ms and Mr R, I am seeking a visually appealing presentation of 3 variables (~30 datapoints) that are correlated and that should to into the same direction. The objective is to show that they do go in the same direction and what differences there might be while also giving an idea of the values of the variables. I had done this with simple bargraphs for 6 datapoints in the past, but for