similar to: How to exclude certain columns by column names?

I'm thinking of using external program 'grep' and pipe() to do so. But I'm wondering if there is a more efficient way to do so purely in R

Hi, I am wondering if some experienced users would help put the ready-to-run code of the examples in the manuals. It would help new users learn R faster by putting all the examples in an ready-to-run R script file. Can somebody help do so sometime and post the code along with the pdf manuals? http://cran.r-project.org/manuals.html Regards, Peng

I don't find a function to print a string to file. Would somebody let me know what function I should use?

Some examples in the help page are too long to be copied from screen. Could somebody let me know some easy way on how to extract the example to a file so that I can play with them?

I found this paper on ANOVA on unequal error variance. Has this be incorporated to any R package? Is there any textbook that discuss the problem of ANOVA on unequal error variance in general? http://www.jstor.org/stable/2532947?cookieSet=1

I don't see where describes the implementation of '[]'. For example, if x is a matrix or a data.frame, how the lookup of 'colname1' is x[, 'colname1'] executed. Does R perform a lookup in the a hash of the colnames? Is the reference O(1) or O(n), where n is the second dim of x?

I don't see where describes the implementation of '[]'. For example, if x is a matrix or a data.frame, how the lookup of 'colname1' is x[, 'colname1'] executed. Does R perform a lookup in the a hash of the colnames? Is the reference O(1) or O(n), where n is the second dim of x?

Hi, I can use the following code to generate a matrix, each column of which is 'x'. But I have to specify '5' twice in the second command. I am wondering if there is a better way to do it. > x=1:10 > matrix(rep(x,5),nc=5) > t(matrix(rep(x,5),nc=5)) Regards, Peng

read.table terminates the program if the input file is empty. Is there way to let the program continue and return me a NULL instead of terminating the program? $ Rscript read_empty.R > read.table("empty_data.txt") Error in read.table("empty_data.txt") : no lines available in input Execution halted $ cat read_empty.R read.table("empty_data.txt") $ cat

Hi, > match(c(3,4), c(3,2,1)) [1] 1 NA The above result has 'NA' in. Is there a way to make 'match' does not produce any 'NA's? Regards, Peng

Hi, I'm learning the tutorial. http://llvm.org/docs/tutorial/ I'm wondering if there is already a git repository of the examples in the tutorial so that I don't have to copy the code from the webpage. Thanks! -- Regards, Peng

Hi, x=matrix(1:60,nr=6) I can refer the last 2 rows by x[5:6,] If I don't know the total number of rows is 6, is there a way to refer the last 2 rows? Regards, Peng

> > but doesn't emit optnone and nounwind attributes > s/nounwind/noinline On Mon, Jan 28, 2019 at 11:35 AM Jakub (Kuba) Kuderski < kubakuderski at gmail.com> wrote: > As far as I understand, gllvm doesn't run LTO pipeline or any cross-module > optimization, and the optimization level provided is only used to compile > each Translation Unit separately. > If you

Hi, > x=c(rep(1,3),rep(3,2)) > x [1] 1 1 1 3 3 > duplicated(x) [1] FALSE TRUE TRUE FALSE TRUE > As shown in the above code, 'duplicated' doesn't return 'F' for the first '1' and first '3' in 'x'. I am wondering if there is a function that can return an indicator for any element whether it appears in a vector twice or more. Regards, Peng

There are a few version of apply() (e.g., lapply(), sapply()). I'm wondering if there is one that does not return anything but just silently apply a function to the list argument. For example, the plot function is applied to each element in 'alist'. It is redundant to return anything from apply. apply(alist,function(x){ plot each element of alist})

Hi, I don't quite understand what are the return values of aov. I know that it has 'coefficients'. But I need to know what all the other return values are. Can somebody let me know how to figure them? Value: An object of class 'c("aov", "lm")' or for multiple responses of class 'c("maov", "aov", "mlm",

Hi, I am wondering how to pop up the graphics window from Rscript. I run the following code, but I don't see the graphics window, even transiently. Regards, Peng $ Rscript plot.R > x=1:10 > y=1:10 > plot(x,y) >

Hi, I'm wondering if R provide a vi mode in the command line just like other shells such as bash do. Can somebody let me know? Regards, Peng

Hi, I am wonder if there is a function similar 'apply' but it could accept multiple arguments? For example, I have the following matrix. x=matrix(1:6,nr=2) y=matrix(1:6,nr=2) I want to find a function that can be used to compute the linear regression for each pair of rows in the two matrices? multiple_apply(x,y,1,function(u,v){lm(u ~ v)} That is, I wound like something like the above

Hi, I have llvm installed through MacPorts. But I don't see macports installed. Are there supposed to be manpages of commands like lli installed? -- Regards, Peng