similar to: Buffering in R 3.5 connections causes incorrect data in readChar

Tomas, Thank you for the explanation. I see in the documentation: "These functions are intended to be used with binary-mode connections." So I see how using it on a text connection is undefined, and not a bug. An error or warning when attempting to use a it on a text connection would be helpful considering how the behavior has changed in R-3.5. On Tue, May 29, 2018 at 3:09 AM, Tomas

On 05/26/2018 05:15 AM, Aaron Goodman wrote: > I noticed an issue where readChar does not return the correct value after a > call to readline. It appears that readChar is not aware of the buffering, > so it reads from the end of the buffer, rather than the current position in > the file. This is a significant change of behavior from R-3.4.4. > > Below is a test case that I used

I am curious why readLines() has a default (n=-1L) to read the full file while readChar() has no default for nchars= (i.e., readChar(file) is an error). Is there a technical reason for this? I often[1] see code like paste(readLines(f), collapse="\n") which would be better served by readChar(), especially given issues with the global string cache I've come across[2]. But lacking the

On Fri, 26 Jan 2024, Michael Chirico wrote: > I am curious why readLines() has a default (n=-1L) to read the full > file while readChar() has no default for nchars= (i.e., readChar(file) > is an error). Is there a technical reason for this? > > I often[1] see code like paste(readLines(f), collapse="\n") which > would be better served by readChar(), especially given

My opinion is that the proposed feature would be greatly appreciated by users. I had always wondered if I was the only one doing paste(readLines(f), collapse="\n") all the time. It would be great to have the proposed, more straightforward way to read the whole file as a string: readChar("my_file.txt", -1) or even better readChar("my_file.txt") Thanks for your detailed

Hi, Here's a patch to the readChar manual page (R-trunk as of today) that better clarifies readChar's return value. It could use some work as I'd also like to add some text about using nchar() to find the length of the string that readchar() returns, but I'm unsure which of type="bytes" or type="chars" to mention. Is it type="chars"? Index:

I have R code to read a binary header file, consisting of several readBin() and readChar() statements. I am currently using version R-2.2.1 (on x86_64, RH EL4) and have received the following error Error in readChar(fid, n = 1) : invalid UTF-8 input in readChar() This is strange because (a) I was able to read in this file successfully in previous versions of R (circa 2005) and (b) it

Hi, I was trying to have R read files faster with readChar(). That was before I noticed that readChar() is not that bad! In any case, below I suggest a few simple changes that will make readChar slightly faster. I followed readChar(useBytes=T), and tried to identify all O(N) operations, where N is the size of the file. The assumption is that for LARGE files we want to avoid any O(N) operations,

Full_Name: Dr. Alex Sheppard Version: 2.7.1 OS: Linux Debian Lenny Submission from: (NULL) (79.73.224.62) After scanning from an open (text) connection, then seeking, then scanning again, the second scan returns incorrect result. It looks like the first byte scanned was from the pre-seek file position, then it continues to read from the post-seek file position. To reproduce: #Put 3x3 matrix

Full_Name: Hugh C. Pumphrey Version: 1.4.1 OS: Linux (Debian Woody) Submission from: (NULL) (129.215.133.170) The function readChar() appears to have some type of problem with memory allocation. I don't know if "memory leak" is the correct term but if one uses readChar() many times, the R binary grows in size until it eats all your memory and swap space. The code enclosed below

Dear list, I am trying to find a fast solution to read moderately large (1 -- 10 million entries) text files containing only tab-delimited numeric values. My test file is the following, nr <- 1000 nc <- 5000 m <- matrix(round(rnorm(nr*nc),3),nr=nr) write.table(m, file = "a.txt", append=FALSE, row.names = FALSE, col.names = FALSE) scan() is faster than

Hi R gurus, I'm trying to use a ReSTful web service from within R. Specifically, I need to make HTTP PUT requests. I'm able to make the request and that goes well enough, but I'm having trouble properly consuming the HTTP response. The problem comes in when I'm trying to parse out the response body. I get the length of the response body from the Content-Length header. I then try

Thanks to all who have responded. My concern was to be able to write a csv file that can have line feeds in string columns chr(10). Why? Excel allows line feeds chr(10) within cells and line breaks chr(13)+chr(10) at line ending, but the windows version of R automatically replaces \n by \r\n in writing and \r\n by \n in reading (text mode). The clues for a solution came from Brian Ripley and

Hello, I am trying to read in elements out of a very large binary file ... the total file is 4 gigs. I want to select rows out of the file, and the current procedure I run works but is prohibitively slow (takes more than a day to run and still won't complete). Is there any faster way to accomplish this? My current procedure looks like this: readHH <- function(file_name,

Hi, I am looking for a way to search a file for position of some expression, from within R. My current code: sha1Pos = gregexpr("<sha1>", readChar(filename, file.info(filename)$size))[[1]] Works fine for small files, but text files I will be working with might get up to Gb range, so I was trying to accomplish the same without loading the whole file into R. I realize this is

Hi all, Since I was having several problems trying to work with a large matrix I started to use the package R.huge but I'm having the following problem > x<-FileByteMatrix("covtype.data",nrow=581012,ncol=55) Error: cannot allocate vector of size 770.8 Mb In addition: Warning messages: 1: Reached total allocation of 447Mb: see help(memory.size) in: readChar(con = con, nchar =

Hi, I started playing around with a function for using StatTransfer (version 10) for importing data. This started as a simple task but it's not working and so now I'm very frustrated. I'm using R version 2.13 on Windows 7. The function, called fn.importData, is: function(file = NULL, type = NULL){ ## ## create statTransfer command file -

Hi: I have also just stumbled into this bug. Unfortunately, I can not change the data my program receives from stdin. My code runs in a larger system and stdin is sent to a Docker container running my R code. The protocol is I read a line, readLines("stdin", n=1), do some actions, send output on stdout, and wait for the next set of data. I don't have control over this protocol, so

Dear All: I am trying to load an R data set, but I got the following message. Please see below. The file is there. setwd("F:/Fall_2017/5-STA574/2-Notes/1-R/1-R_new/chapter4-Entering_Data") datahs0csv <- read.table("hs0.csv", header=T, sep=",") attach(datahs0csv) detach(datahs0csv) rm(list=ls()) Then I tried to reload the data, but I got this error message. I

Hi, I have a flat file that contains a bunch of strings that look like this. The file was originally in Unix and brought over into Windows: E123456E234567E345678E456789E567891E678910E. . . . Basically the string starts with E and is followed with 6 numbers. One string=E123456, length=7 characters. This file contains 10,000's of these strings. I want to separate them into one vector the