similar to: Converting a data frame to matrix

I noticed something surprising (in R 2.2.1 on WinXP) According to the documentation, rownames and colnames are character vectors. Assigning a vector of class POSIXct or POSIXlt as rownames or colnames therefore is not strictly according to the rules. In some cases, R performs a reasonable typecast, but in some other cases where the same typecast also would be possible, it does not. Assigning a

I noticed something surprising (in R 2.2.1 on WinXP) According to the documentation, rownames and colnames are character vectors. Assigning a vector of class POSIXct or POSIXlt as rownames or colnames therefore is not strictly according to the rules. In some cases, R performs a reasonable typecast, but in some other cases where the same typecast also would be possible, it does not. Assigning a

Hi all I was wondering whether there has ever been an update on the rownames and colnames behaviour as described by Eric below? I still get the same behaviour, exactly as described by Eric, on my WinXP installation of R-2.3.0. I also posted a message to r-help on Friday but looking through the online archives it seems to have not made it to the list. I would agree with Eric that a consistent

Dear Group: I am working with a data frame containing 316 rows of individuals with 79 variables. Each of these 79 variables have values that range between -4 to +4, and I want to subset this data frame so that in the resulting new dataframe, values of _all_ of these variables should range between -3 and +3. Let's say I have the following dataframe (it's a toy example with 4 individuals

Matti - Since you are asking about looping through a column, not looping across columns, it is simply the following: # Note: data.frame() turns strings into factors by default. myDF <- data.frame(type = c("a", "j", "a", "a", "j"), weight = c(12.3, 6.8, 10.5, NA, "5.5")) myDF$type # ... is a vector of factors

Boris: "As others have remarked, for added efficiency with large datasets we often use functions from the apply() family, rather than for-loops." That is generally false, though it is a common misconception. Apply-type functions are used to maintain fidelity -- and for some, clarity -- to a functional programming paradigm. Cheers, Bert Bert Gunter "The trouble with having an

Hello! # I have a data frame: mydf<-data.frame(c1=rep(NA,5),c2=rep(NA,5),c3=rep(NA,5)) # I have an index whose length is always the same as nrow(mydf): myindex<-c(1,2,3,2,1) # I need c1 to have 1s in rows 1 and 5 (based on the information in myindex) # I need c2 to have 1s in rows 2 and 4 (also based on myindex) # I need c3 to have 1 in row 3 # In other words, I am trying to achieve this

I am a relatively new user to R, and I am trying to learn more about converting data in an XML document into "2-dimensional format" such as a table or array. I might eventually wish to export this data into a relational database such as SQL, and/or to work with this data within the R package. My sample XML document is located at "

Hi Kevin, I think there are issues with Rui's proposed solution. For example, if there are rows in myDF1 which have a studyno which does not match any row in myDF2, then you will lose those rows. In your original request you said that you wanted to keep those rows. To demonstrate my point I need to modify your sample data. Specifically, I changed some studyno settings in myDF1, and also the

Hello, Try the following. myDF1$studyno <- as.character(myDF1$studyno) myDF2$studyno <- as.character(myDF2$studyno) i1 <- which(names(myDF1) == "pf_mcl") merge(myDF1[-i1], myDF2, by = "studyno") Hope this helps, Rui Barradas Em 13-10-2017 20:09, Kevin Wamae escreveu: > I'm trying to populate the column ?pf_mcl? in myDF1 with values from myDF2, where rows

Dear @Rui Barradas, thank you for the solution. It works perfectly. On 13/10/2017, 23:35, "Rui Barradas" <ruipbarradas at sapo.pt> wrote: Hello, Try the following. myDF1$studyno <- as.character(myDF1$studyno) myDF2$studyno <- as.character(myDF2$studyno) i1 <- which(names(myDF1) == "pf_mcl") merge(myDF1[-i1], myDF2,

I'm trying to populate the column ?pf_mcl? in myDF1 with values from myDF2, where rows match based on column "studyno" but the solutions I have found so far don't seem to be giving me the desired output. Below is a snapshot of the data.frames. myDF1 <- structure(list(studyno = c("J1000/9", "J1000/9", "J1000/9", "J1000/9",

Your example used one distinct studyno in DF1 and one distinct pf_mcl in DF2. I think that makes it hard to see what is going on, but maybe I completely misunderstand the problem. In any case, let's redefine myDF1 and myDF2. Note that myDF1 contains a studyno not in myDF2 and vice versa. myDF1 <- structure(list(studyno = c("J1000/9", "J895/7", "J931/6",

Dear @William<mailto:wdunlap at tibco.com>, thanks for the feedback. I have tested it on the larger dataset and noticed that it created two variables, pf_raw and pf_curated. The output we were looking for, was one that takes the variable pf_mcl in curated dataset and replaces pf_mcl in matching rows within the raw dataset. @Eric<mailto:ericjberger at gmail.com>?s solution was able to

?merge Bert On Oct 13, 2017 12:09 PM, "Kevin Wamae" <KWamae at kemri-wellcome.org> wrote: > I'm trying to populate the column ?pf_mcl? in myDF1 with values from > myDF2, where rows match based on column "studyno" but the solutions I have > found so far don't seem to be giving me the desired output. > > Below is a snapshot of the data.frames. >

Hello, I know, this is a real newbie question, but I can't find anything on this in the manuals! I know that I get calculate the column totals of a table with `apply(mytable, 2, sum)'. Now I want each column total to be 100% and calculate the percentage of each field of the column. How would I do that? Rcommander, the ultimate newb-tool, has a function `colPercents' which is exactly

Dear @Bert Gunter<mailto:bgunter.4567 at gmail.com>, I tried merge and I faced many challenges. @Rui Barradas<mailto:ruipbarradas at sapo.pt> solution is working. From: Bert Gunter <bgunter.4567 at gmail.com> Date: Friday, 13 October 2017 at 22:44 To: Kevin Wamae <KWamae at kemri-wellcome.org> Cc: R-help <R-help at r-project.org> Subject: Re: [R] Populate one data

Dear R-devs, Below is a small example of what I am trying to achieve, that is trivial in R and I would like to learn how to do in C, for very large matrices: > (mymat <- matrix(c(1,0,0,2,2,1), nrow = 2)) [,1] [,2] [,3] [1,] 1 0 2 [2,] 0 2 1 And I would like to produce: [1] "a*C" "B*c" Which can be trivially done in R via something like: foo

Hi Group, I have a matrix, and I would like to replace numbers less than 0 by the smallest minimum number. Below is an small matrix, and the loop I used. I would like to get suggestions on the "R way" to do this. Thanks, Juliet # example data set mymat <- structure(c(-0.503183609420937, 0.179063475173256, 0.130473004669938, -1.80825226960127, -0.794910626384209, 1.03857280868547,

Dear R-experts, I have found a splom-modification online which is given below. This works perfectly, but I would like to have a matrix of given correlation values to be used in the lower triangular part (lower.panel) of the splom-plot instead of calculated correlation values. Here is the matrix I would like to use (it can be any other convenient data structure):