similar to: check whether connection can be opened

Hey all, I learned that using the equals sign "=" to assign objects is generally OK, but will not work in some cases. As I always use "<-" for assignments, I have not encoutered any problems. Could somebody provide an example or explanation, why getting used to "=" is not a good idea? Or is it? Thanks ahead, Berry ------------------------------------- Berry

Hello dear developers, I find myself often having the result of "range" oder "extendrange", which I want to create a sequence with. But "seq" needs two seperate arguments "from" and "two". Could an argument "range" be added? Otherwise I will have to create an object with the range (may come from a longer calculation), index twice from

hi, say I have consecutively numbered objects obj1, obj2, ... in my R workspace. I want to acces one of them inside a function, with the number given as an argument. Where can I find help on how to do that? Somebody must have been trying to do this before... Some keywords to start a search are appreciated as well. Here's an example, I hope it clarifies what I'm trying to do: obj1 <-

Hello, >From the doc, it says: "isOpen returns a logical value, whether the connection is currently open." But actually it seems to die on closed connections: > con <- file() > isOpen(con) [1] TRUE > close(con) > isOpen(con) Error in isOpen(con) : invalid connection Is it expected ? Tested on R-3.0.2 and R version 3.1.0 Patched (2014-06-11 r65921) on linux x86_64

I noticed the following file descriptor leak when I couldn't remove a package unless I shut down the R session that had loaded and used it. The function that triggered the problem printed the output of a call to parse(). Each time one prints a srcref a connection is opened and not closed. It looks like it happens in as.character.srcref's call to getSrcLines, which has some logic I

As far as I can tell, 'isOpen' cannot return FALSE in the case when 'rw = ""'. If the connection has already been closed by 'close' or some other function, then isOpen will produce an error. The problem is that when isOpen calls 'getConnection', the connection cannot be found and 'getConnection' produces an error. The check to see if it is

Hi! I'm wondering if there's a smart way around this: fileName= (some valid file on your system) > fileCon=file(fileName, open="rt") > l<-readLines (fileCon, n= 1) > > isOpen(fileCon) [1] TRUE > close(fileCon) > isOpen(fileCon) Error in isOpen(fileCon) : invalid connection How do you test for a file being closed if isOpen gives you an error

Dear all, I do not completely understand following behaviour : > con <- file("test.txt") > isOpen(con) [1] FALSE > open(con) > isOpen(con) [1] TRUE > close(con) > isOpen(con) Error in isOpen(con) : invalid connection > str(con) Classes 'file', 'connection' atomic [1:1] 3 ..- attr(*, "conn_id")=<externalptr> Why do I get an

Hello, I have R as a socket server that computes R code sent by some scripts (the clients). These scrips send R code to generate models (SVM). The problem is that first models are generated in less than one second and one hour later, the same models are generated in more than ten seconds (even training with same data). If I restart the server , then it works well (fast). I don't know if I have

> # creating a file > cat("sddfasdf", file="tempfile") > showConnections() class description mode text isopen can read can write > con <- file("tempfile", "r") > readLines(con) [1] "sddfasdf" Warning message: incomplete final line in: readLines(con, n, ok) > showConnections() class description mode text isopen

SUMMARY: I'm proposing that R assert that 'connection' options have not changed since first created such that R will produce the following error: > fh <- file("a.txt", open = "w+") > cat("hello\n", file = fh) > close(fh) > fh2 <- file("b.txt", open = "w+") > cat("world\n", file = fh2) >

Hi everyone, I'm trying to print a table justified to the left, but it doesn't work. Any hints? KennArt <- data.frame(NR=c(171,172,174,175,176,177,181,411,980), TYP=c("K?rnermais", ?"Corn Cob Mix", "Zuckermais", "Mischanbau (Silo)Mais/Sonnenblumen", ?"Mais mit Bejagungsschneise in gutem landwirtschaftlichen und ?kologischen Zustand",

I'm been doing more and more of file text parsing inside R instead of coping with Perl. For that, I need open a file and read it line-by-line. I found the documentation for 'open' isn't very clear. Right now it has ,----[ *help(R)[open]* ] | 'open' opens a connection. In general functions using connections | will open them if they are not open, but then close them

Hi, I am making multiple calls to gzfile() via read.table(), e.g. > x <- read.table( gzfile( "xxx.gz" ) ) After i do this many times (I haven't counted, but probably between 50 and 100 times) I get the error message: Error in open.connection(file, "r") : unable to open connection In addition: Warning message: cannot open compressed file 'xxx.gz' however, I

On Thu, Dec 14, 2017 at 7:56 PM, Gabriel Becker <gmbecker at ucdavis.edu> wrote: > Gabor, > > You can grab the connection and destroy it via getConnection and then a > standard close call. Yeah, that's often a possible workaround, but since this connection was opened by readLines() internally, I don't necessarily know which one it is. E.g. I might open multiple

Thought I'd try and start a discussion. Feel free to jump in. I guess R needs to strike the right balance between opening up the internals to package writers and not allowing them to do bad things. My first attempt at cracking this nut is to just memcpy() the Rconnection and not allow access to the private stuff: /* Alternative to allowing C code access to connection API. */ Rconnection

Using dup() before fdopen() (and calling fclose() on the connection when it is closed) indeed fixes the memory leak. FYI, Gabor Index: src/main/connections.c =================================================================== --- src/main/connections.c (revision 71653) +++ src/main/connections.c (working copy) @@ -576,7 +576,7 @@ fp = R_fopen(name, con->mode); } else { /* use

Hi all, I am trying to create a function that will open connections to all files of one type within the working directory. I've got the function to open the connections, but I am having a bugger of a time trying to get these connections named as objects in the workspace. I am at the point where I can do it outside of the function, but not inside, using assign. I'm sure I'm

Consider this code. This is R 3.4.2, but based on a quick look at the NEWS, this has not been fixed. tryCatch( readLines(tempfile(), warn = FALSE)[1], error = function(e) NA, warning = function(w) NA ) rm(list=ls(all.names = TRUE)) gc() showConnections(all = TRUE) If you run it, you'll get a connection you cannot close(), i.e. the last showConnections() call prints: ?

help on showConnections explains parameter all logical: if true all connections, including closed ones and the standard ones are displayed. If false only open user-created connections are included. but > # create a file > cat("TITLE extra line", "2 3 5 7", "", "11 13 17", file="ex.data", + sep="\n") >