I know that the sink() function can be used to divert R output into a file, e.g.
sink('sink-closing.txt')
cat('Hello world!')
sink()
Is there a simple command to close all outstanding sinks?
Below, I elaborate on my question.
Suppose that my R-script opens a sink() in an R-script, but there is an error in the R-script which occurs before the script closes the sink(). I may run the R-script multiple times, trying to fix the error. Finally, I want to close all the sinks and print to the console. How do I do so?
Finally, in the interest of concreteness, I provide a MWE to illustrate the problem I face.
First, I write an R-script sink-closing.R which has an error in it.
sink('sink-closing.txt')
foo <- function() {
cat(sprintf('Hello world! My name is %s\n',
a.variable.that.does.not.exist))
}
foo()
sink()
Next, I source the R-script multiple times, say 3 times by mistake as I try to find and fix the bug.
> source('~/Dropbox/cookbook/r-cookbook/sink-closing.R')
Error in sprintf("Hello world! My name is %s\n", a.variable.that.does.not.exist) :
object 'a.variable.that.does.not.exist' not found
Now, suppose that I am debugging the R-script and want to print to the console. I can call sink() multiple times to close the earlier sinks. If I call it 3 times, then I can finally print to the console as before. But how do I know how many sinks I need to close?
closeAllConnections() # .........................
I'm getting upvotes for this as time goes along but Simon.S.A and others are better.
You can use sink.number() to tell you how many diversions are already set and then call sink that many times. Putting it into a function you could have this
sink.reset <- function(){
for(i in seq_len(sink.number())){
sink(NULL)
}
}
Based on #mnel's comment:
sinkall <- function() {
i <- sink.number()
while (i > 0) {
sink()
i <- i - 1
}
}
Should close all open sinks.
You may also encounter this problem when dealing with devices and plots, where the number of open devices isn't reported anywhere. For a more general case you could use this:
stopWhenError <- function(FUN) {
tryCatch({
while(TRUE) {
FUN()
}
}, warning = function(w) {
print("All finished!")
}, error = function(e) {
print("All finished!")
})
}
stopWhenError(sink) # for sink.
stopWhenError(dev.off) # close all open plotting devices.
EDIT:
sink throws a warning not an error so I've modified the code so that it won't run forever, whoops!
The most common time I experience this is when an error occurs preventing a sink from closing. For example, the following will leave an open sink after execution.
sink("output.txt")
my_function_that_will_error()
sink()
This can be avoided using on.exit(sink()). This will close the sink "when the current function exits (either naturally or as the result of an error)" (documentation here).
But you do have to change the order:
sink("output.txt")
on.exit(sink())
my_function_that_might_error()
So we create the sink, tell R to close it when it exits, and then execute the code that might error. This will close the sink regardless of whether the code errors or not.
Related
I'm using a package function (corenv, from seewave) which create a "please wait..." message in console. As I call it iteratively, that message is very annoying. So, I need a way for:
From my code, to temporarily ban the console messages
OR
To access the function code and take off the message line
The following is not my real code, but a very simple one showing the problem
require(seewave)
a = seq(0, (2*pi), by=0.01) #simple, unreal example
for (i in sequence(100)){
x = sin(a*i/3) #simple, unreal example
y = sin(a*i/2) #simple, unreal example
corenv(x,y,10,plot=FALSE)
}
A very simple question, but I haven't found any solution. I'll aprecciate any help
You could use sink to capture the output, e.g.
sink("tmp.txt")
z = corenv(x,y,10,plot=FALSE)
sink()
You can also wrap it in a function, e.g.
## unlink deletes the temporary file
## on.exit ensures the sink is closed even if
## corenv raises an error.
corenv(..., verbose=FALSE) {
if(verbose) {
sink("tmp.txt")
on.exit(sink(); unlink("tmp.txt"))
}
seewave::corenv(...)
}
I am closing the device (here: pdf() ) I am plotting to at the end of my function with dev.off(). However, if the function/loop terminates due to an error the device stays open. When a function gets repeatedly called, this can lead to quite a lot of open devices; and file handles.
How can I make sure the device gets closed even if the function fails?
I do remember that I once saw how to do this, but I cannot remember.
on.exit() is made for situations just like this. It's good practice to use it whenever opening a (file or other) connection in a non-interactive setting.
f <- function() {
pdf(tempfile()) # tempfile() so example doesn't clutter up working directory.
on.exit(dev.off())
plot(randomNonExistentObjectName)
}
f()
# Error in plot(randomNonExistentObjectName) :
# object 'randomNonExistentObjectName' not found
dev.list()
# NULL
Wrap your whole plotting expression into a tryCatch like so:
tryCatch(expr={pdf(...); plot(...)}, finally=dev.off())
So I am using a function in R that uses compiled fortran code. While using this function, lsoda, in package deSolve. I get messages printed to the screen like
DLSODA- At current T (=R1), MXSTEP (=I1) steps
taken on this call before reaching TOUT
In above message, I =
[1] 5000
In above message, R =
[1] 21.31629
The problem is that the above is not a "warning" or an "error"; the is.null(warnings()) evaluates to TRUE after I see this message. If it were a warning I could just write x = is.null(warnings()) and that would do the trick. I could use tryCatch for errors, but what about messages that are neither errors or warnings?
The reason I ask, is that this function is called in a while loop, inside a for loop. I want the while loop to break if this message gets printed, and then for the outer for loop to move onto the next iteration. Normally you'd use tryCatch to do something like this but because there is no error, I have no idea how to do this
You can redirect the output and then check whether lsoda printed something:
out <- capture.output(lsoda(...))
if(length(grep("In above message", out))!=0) {
# error
}
We basically check whether any of the lines printed by lsoda contains the string In above message. If you need to use the result from lsoda, you can also run like this:
out <- capture.output(result <- lsoda(...))
As suggested, you can also use grepl:
if(any(grepl("In above message", out))) {
# error
}
I am running an optimization program I wrote in a multi-language framework. Because I rely on different languages to accomplish the task, everything must be standalone so it can be launched through a batch file. Everything has been going fine for 2-3 months, but I finally ran out of luck when one of the crucial parts of this process, executed through a standalone R script, encountered something new and gave me an error message. This error message makes everything screech to a halt despite my best efforts:
selMEM<-forward.sel(muskfreq, musk.MEM, adjR2thresh=adjR2)
Procedure stopped (adjR2thresh criteria) adjR2cum = 0.000000 with 0 variables (superior to -0.005810)
Error in forward.sel(muskfreq, musk.MEM, adjR2thresh = adjR2) :
No variables selected. Please change your parameters.
I know why I am getting this message: it is warning me that no variables are above the threshold I have programmed to retain during a forward selection. Although this didn't happen in hundreds of runs, it's not that big a deal, I just need to tell R what to do next. This is where I am lost. After an exhaustive search through several posts (such as here), it seams that try() and tryCatch() are the way to go. So I have tried the following:
selMEM<-try(forward.sel(muskfreq, musk.MEM, adjR2thresh=adjR2))
if(inherits(selMEM, "try-error")) {
max<-0
cumR2<-0
adjR2<-0
pvalue<-NA
} else {
max<-dim(selMEM)[1]
cumR2<-selMEM$R2Cum[max]
adjR2<-selMEM$AdjR2Cum[max]
pvalue<-selMEM$pval[max]
}
The code after the problematic line works perfectly if I execute it line by line in R, but when I execute it as a standalone script from the command prompt, I still get the same error message and my whole process screeches to a halt before it executes what follows.
Any suggestions on how to make this work?
Note this in the try help:
try is implemented using tryCatch; for programming, instead of
try(expr, silent = TRUE), something like tryCatch(expr, error =
function(e) e) (or other simple error handler functions) may be more
efficient and flexible.
Look to tryCatch, possibly:
selMEM <- tryCatch({
forward.sel(muskfreq, musk.MEM, adjR2thresh=adjR2)
}, error = function(e) {
message(e)
return(NULL)
})
if(is.null(selMEM)) {
max<-0
cumR2<-0
adjR2<-0
pvalue<-NA
} else {
max<-dim(selMEM)[1]
cumR2<-selMEM$R2Cum[max]
adjR2<-selMEM$AdjR2Cum[max]
pvalue<-selMEM$pval[max]
}
Have you tried setting the silent parameter to true in the Try function?
max<-0
cumR2<-0
adjR2<-0
pvalue<-NA
try({
selMEM <- forward.sel(muskfreq, musk.MEM, adjR2thresh=adjR2)
max<-dim(selMEM)[1]
cumR2<-selMEM$R2Cum[max]
adjR2<-selMEM$AdjR2Cum[max]
pvalue<-selMEM$pval[max]
}, silent=T)
I have written a function, which takes some time to run (due to a 1000+ loop on a huge dataset in combination with forecasting model testing).
To have any idea on the status, while the function is called, I use the message command inside the for-loop in the function. The problem is that all the messages are shown in the console after the function is finished, instead of showing immediately. So it doesn't help me :)
I tried to find a solution on Stackoverflow, but didn't found one. I looked for instance on the question "showing a status message in R". All answers and example codes in that topic still give me only text in the console after a function is processed instead of immediately.
How to solve this? Is there maybe a setting in R which prevents immediate printing of message text in the console?
note: examples I tried below, which give the same results as my function; showing text after processing the function.
example1 (Joshua Ulrich):
for(i in 1:10) {
Sys.sleep(0.2)
# Dirk says using cat() like this is naughty ;-)
#cat(i,"\r")
# So you can use message() like this, thanks to Sharpie's
# comment to use appendLF=FALSE.
message(i,"\r",appendLF=FALSE)
flush.console()
}
example2 (Tyler):
test.message <- function() {
for (i in 1:9){
cat(i)
Sys.sleep(1)
cat("\b")
}
}
edit: the first example does work ('flush console' was the problem)...but when I tested it, I commented out flush console for some reason :S
test.message <- function() {
for (i in 1:9){
cat(paste(as.character(i),'\n'))
flush.console()
Sys.sleep(1)
}
}
which is similar to the recommendation by fotNelton.
Edit: ttmaccer is most likely right. I've just tested on a Ubuntu server and the code works without flushing the console.
I seem to think this maybe a windows specific problem. On linux or running R in a cygwin shell the flush.console() may not be needed.
You may be interested in using one of the progress bar functions (winProgressBar, tkProgressBar, or txtProgressBar). The win version only works on windows, but the win and tk versions have the advantage that they do not clutter your output, but rather open another small window and display the progress there.
The progress through a loop can be shown with the progress bar, but other detailed information can be updated and shown with the label argument.