search for: christodoulou

Hi all! I am new to R and I would like to ask you the following question:How can I substitute the NA values with 0 in a data frame? I cannot find a command to check if a value is NA... Thank you very much! Eleni

Hi all, I am trying to install the package "GEOquery" in unix. I have downloaded the standard version of R and this package is not contained in the default. I know that I can select repositories under windows but I don't know how to do it in unix. Does anyone have any idea on this? Thank you in advance, Eleni [[alternative HTML version deleted]]

Hi all, I am trying to draw a Kaplan-Meier curve and I found online that Kaplan - Meier estimates are computed with a function called km in the event package. Is there an update for that because when I choose to download packages in R,. there is no package called event, even though I have selected all the repositories. Thanks in advance, Eleni [[alternative HTML version deleted]]

...s of the model are not included in the first argument of the output but in the result of coef(model), am I right? Moreover, what does the scale argument represent? Which is its connection with the coefficients? The R help file os not very informative for me... Thank you very much in advance, Eleni Christodoulou [[alternative HTML version deleted]]

Hello list, I am trying to apply the paired t.test between diseased and not diseased patients to identify genes that are more expressed in the one situation under the other. In order to retrieve the genes that are more expressed in the positive disease state I do: p.values<-c() for(i in 1:length(Significant[,1])){ p.values[i]<-try(t.test(positive[i,],negative[i,],alternative

Hi everyone, I have a vector with atmospheric measurements (x-axis) that is obtained/calculated at different altitudes (y-axis). The altitude is uniformly distributed every 7 meters. For example my dataframe is: df <- dataframe( *altitude* = c(1005, 1012, 1019, 1026, 1033, 1040, 1047, 1054, 1061, 1068), *atm_values* = c(1.41, 1.40, 1.39, 1.38, 1.37, 1.37, 1.38, 1.36, 1.33, 1.31)

Hi list! I have recently tried to take my office work home, meaning that I tried to transfer my "... .RData" workspace from my PC on my laptop. The office PC runs on Windows XP and my laptop runs on Windows Vista. I have saved the workspace at the office PC and kept it in a usb drive. When I tried to open it on my laptop I got an error: "Fatal Error: Unable to restore saved data in

On 21 Oct 2002, Shelena V Christodoulou <Shelena@imacscontrols.com> wrote: > My UPS died and now my back up is no longer running Hi, I think you have the wrong address. samba-csadmin is for people who want to be in the database of commercial support providers. If you want to obtain support from a company in your area, please...

Hi Konstantinos Not exactly derivative but > diff(df[,2]) [1] -0.01 -0.01 -0.01 -0.01 0.00 0.01 -0.02 -0.03 -0.02 May be enaough for you. Cheers Petr > > -----Original Message----- > From: R-help <r-help-bounces at r-project.org> On Behalf Of konstantinos > christodoulou > Sent: Tuesday, January 31, 2023 10:16 AM > To: r-help mailing list <r-help at r-project.org> > Subject: [R] How to calculate the derivatives at each data point? > > Hi everyone, > > I have a vector with atmospheric measurements (x-axis) that is > obtained/calculate...

Hello all! I am performingsome clustering analysis on microarray data using agnes{cluster} and I have created my own dissimilarity matrix according to a distance measure different from "euclidean" or "manhattan" etc. My question is, if I choose for example method="complete", how are the distances between the elements calculated? Are they taken form the dissimilarity

i want to estimate parameters with maximum likelihood method with contraints (contant numbers). for example sum(Ai)=0 and sum(Bi)=0 i have done it without the constraints but i realised that i have to use the contraints. Without constraints(just a part-not complete): skellamreg_LL=function(parameters,z,design) { n=length(z); mu=parameters[1]; H=parameters[2]; Apar=parameters[3:10];

...ity of Melbourne, VIC 3010 Australia Tel: (+61) 0403 138 955 Email: apro at unimelb.edu.au Website: https://researchers.ms.unimelb.edu.au/~apro at unimelb/ I acknowledge the Traditional Owners of the land I inhabit, and pay my respects to their Elders. On 31 Jan 2023 at 8:17 PM +1100, konstantinos christodoulou <konstantinos.christodoulou1 at gmail.com>, wrote: External email: Please exercise caution Hi everyone, I have a vector with atmospheric measurements (x-axis) that is obtained/calculated at different altitudes (y-axis). The altitude is uniformly distributed every 7 meters. For example my da...

Hi Kostas, The function vectorField in the plotrix package may do what you want. See the example. Jim On Tue, Jul 25, 2023 at 9:30?PM konstantinos christodoulou <konstantinos.christodoulou1 at gmail.com> wrote: > > Dear Rcommunity, > > I hope this email finds you well. I am writing to seek your assistance with > a data visualization problem I am facing while working with R. > > Problem Description: > > I have a dataframe na...

Hello R users, I am trying to run a cox model for the prediction of relapse of 80 cancer tumors, taking into account the expression of 17000 genes. The data are large and I retrieve an error: "Cannot allocate vector of 2.4 Mb". I increase the memory.limit to 4000 (which is the largest supported by my computer) but I still retrieve the error because of other big variables that I have in

Dear Rcommunity, I hope this email finds you well. I am writing to seek your assistance with a data visualization problem I am facing while working with R. Problem Description: I have a dataframe named "df" containing the following columns: "longitude", "latitude", "sea_currents_mag", and "sea_currents_direction". The dataframe includes sea

Hello everyone, I wanted to know if it was possible to change the color of certain leaves in a hclust object in order to make my graph more readable. I know I can color certain groups but I would like to enter a vector telling the plot function which leaves to color in which color. Thanks in advance, Eleni [[alternative HTML version deleted]]

Hello list, I am trying to perform ROC analysis and count the AUC in order to validate my results. I use package ROCR. I would like to count the AUC not under the cutoff found by "performance" but to use another cutoff that I calculate. How could I change the following command in order to get what I want? perform=performance(pred,measure="auc",x.measure="cutoff"),

Hello list! I have a proble trying to perform a SAM analysis using the function samr from the samr package. I have put the option *center.arrays=TRUE *in order to scale all the experiments to median=0. I would like to retrieved the scaled data but it seems that samr does not return it...Does anyone have any idea on this? Thanks a lot!!! E. [[alternative HTML version deleted]]

Dear kind R-experts. with miximum likelihood method i found the following estimations for my parameters vector: mu H A1 A2 . . . A10 D1 D2 . . . D10 but i want to add sum to zero constraints. sum(a1:a10)=0 and sum(d1:d10)=0 how i will do this? _________________________________________________________________ Show them the way! Add maps and directions to your party invites. [[alternative HTML

Dear R users, I am trying to apply SVM regression for a set of microarray data. I am using the function svm() under the package {e1071}. Can anyone tell me what the *residuals *value represents? I have some observed values *y_obs* for the parameter that I want to estimate and I would expect that *svm$residuals = y_obs - svm$fitted. *However, this does not happen...Does anyone have any idea on