Following code in R shiny application (Server side) gives the result as shown below. But can we make this error message disable? Like we do no need any message to be shown. Can we achieve this?
options(shiny.sanitize.errors = TRUE)
Result in Console (In Red)
Error : An error has occurred. Check your logs or contact the app author for clarification
Expected result :
or
"No table" (The user can type anything he needs?)
As mentioned by #nopassport1, the best option is to prevent the error in the first place.
Alternatively, on a case-by-case basis you can remove the error warning by wrapping code in a try(x,silent = TRUE) function.
> try(1+"a")
Error in 1 + "a" : non-numeric argument to binary operator
> try(1+"a",silent = TRUE)
>
Related
Using the syuzhet package in R, the following works but returns a warning message:
object <- get_text_as_string("path/name.txt")
When I put this in a function, it returns the same warning error but does NOT change the value of object:
gen <- function(file){
object <- get_text_as_string(file)
}
gen("path/name.txt")
This is the warning message, if it matters:
Warning message:
In readLines(path_to_file) :
incomplete final line found on 'path/name.txt'
...but again, I get that from get_text_as_string() when used outside of the function, but it DOES change the value of object.
Anyone have any advice? There must be something I don't understand about functions?
(I've looked for similar questions/answers, if I've missed the right one I'd be happy to just be directed there.)
I got the error message:
Error: object 'x' not found
Or a more complex version like
Error in mean(x) :
error in evaluating the argument 'x' in selecting a method for function 'mean': Error: object 'x' not found
What does this mean?
The error means that R could not find the variable mentioned in the error message.
The easiest way to reproduce the error is to type the name of a variable that doesn't exist. (If you've defined x already, use a different variable name.)
x
## Error: object 'x' not found
The more complex version of the error has the same cause: calling a function when x does not exist.
mean(x)
## Error in mean(x) :
## error in evaluating the argument 'x' in selecting a method for function 'mean': Error: object 'x' not found
Once the variable has been defined, the error will not occur.
x <- 1:5
x
## [1] 1 2 3 4 5
mean(x)
## [1] 3
You can check to see if a variable exists using ls or exists.
ls() # lists all the variables that have been defined
exists("x") # returns TRUE or FALSE, depending upon whether x has been defined.
Errors like this can occur when you are using non-standard evaluation. For example, when using subset, the error will occur if a column name is not present in the data frame to subset.
d <- data.frame(a = rnorm(5))
subset(d, b > 0)
## Error in eval(expr, envir, enclos) : object 'b' not found
The error can also occur if you use custom evaluation.
get("var", "package:stats") #returns the var function
get("var", "package:utils")
## Error in get("var", "package:utils") : object 'var' not found
In the second case, the var function cannot be found when R looks in the utils package's environment because utils is further down the search list than stats.
In more advanced use cases, you may wish to read:
The Scope section of the CRAN manual Intro to R and demo(scoping)
The Non-standard evaluation chapter of Advanced R
While executing multiple lines of code in R, you need to first select all the lines of code and then click on "Run".
This error usually comes up when we don't select our statements and click on "Run".
Let's discuss why an "object not found" error can be thrown in R in addition to explaining what it means. What it means (to many) is obvious: the variable in question, at least according to the R interpreter, has not yet been defined, but if you see your object in your code there can be multiple reasons for why this is happening:
check syntax of your declarations. If you mis-typed even one letter or used upper case instead of lower case in a later calling statement, then it won't match your original declaration and this error will occur.
Are you getting this error in a notebook or markdown document? You may simply need to re-run an earlier cell that has your declarations before running the current cell where you are calling the variable.
Are you trying to knit your R document and the variable works find when you run the cells but not when you knit the cells? If so - then you want to examine the snippet I am providing below for a possible side effect that triggers this error:
{r sourceDataProb1, echo=F, eval=F}
# some code here
The above snippet is from the beginning of an R markdown cell. If eval and echo are both set to False this can trigger an error when you try to knit the document. To clarify. I had a use case where I had left these flags as False because I thought i did not want my code echoed or its results to show in the markdown HTML I was generating. But since the variable was then used in later cells, this caused an error during knitting. Simple trial and error with T/F TRUE/FALSE flags can establish if this is the source of your error when it occurs in knitting an R markdown document from RStudio.
Lastly: did you remove the variable or clear it from memory after declaring it?
rm() removes the variable
hitting the broom icon in the evironment window of RStudio clearls everything in the current working environment
ls() can help you see what is active right now to look for a missing declaration.
exists("x") - as mentioned by another poster, can help you test a specific value in an environment with a very lengthy list of active variables
I had a similar problem with R-studio. When I tried to do my plots, this message was showing up.
Eventually I realised that the reason behind this was that my "window" for the plots was too small, and I had to make it bigger to "fit" all the plots inside!
Hope to help
I'm going to add this on here even though it's not a new question as it comes quite highly in the search results for the error:
As mentioned above, re checking syntax, if you're using dplyr, make sure you have all the %>% pipes at the end of the lines above the error, otherwise the contents of anything like a select statement won't pass down into the next part of the code block.
I know about tryCatch to customize error message. But is there a way to incorporate messages when there is no error. For example the below code does not show any error. But can we print like " No error and the code is good"
a <- 2+6 # we get no error here.
You can add lines in your code to notify you like below :
a <- 2+6
cat('Everything in fine at this line')
The following code sends output to the console when the expression fails even though the try() argument silent = TRUE.
dd = try(unlist(remDr$findElement("css", "#ctl00_mainA")), silent = TRUE)
suppressMessages() does not suppress the output.
dd = suppressMessages(try(unlist(remDr$findElement("css", "#ctl00_mainA")), silent = TRUE))
try() is used to trap the error Selenium message: Unable to locate element: ......... The code logic works perfectly; the script continues to run as intended.
The message is not an Error that appears in red. The message is in black; the same color that results from print() and cat().
Echo is off. The source code does not print to the console.
I want to suppress the message while retaining the ability to send messages to the console with print() and cat().
Would appreciate any ideas.
Use remDr$findElements() instead with the same arguments. If the element you are looking for doesn't exist it just returns a zero length list which is easy to test for, and you don't get a lengthy error message printed to the console.
In my efforts to work around the issue mentioned here:
MonetDB connect to GO.db within R code that is run in-database
I went ahead and copied the code from WGCNA that I needed to my own package and installed it. Obviously, I now can load the package without any issues (since I didn't need the GO.db part).
However, I seem to run into another issue:
Server says '!Error running R expression. Error message: Error in
.C("corFast", x = as.double(x), nrow = as.integer(nrow(x)), ncolx =
as.integer(ncol(x)), : '.
I indeed wanted to use the faster cor function from WGCNA, but apparently the C call now creates another issue.
Unfortunately, the message is not informative. I already tried to run the query interactively and adding debug to the statement. This did not provide me with more information.
Is there anything that I can do to increase the verbosity, so that I can debug the proces?
I also tried:
options(monetdb.debug.query=F)
This resulted in a bit of extra output prior to the query, but no extra output on the error that occurred.
Using the suggestion of Hannes Muehleisen I added:
options(monetdb.debug.mapi=T)
It does add a little more information, which allowed me to proceed a bit further. I am now stuck with the following error, which seems again truncated.
QQ: 'SELECT * FROM cor_test();' TX: 'sSELECT * FROM cor_test(); ; RX:
'!Error running R expression. Error message: Error in .C("corFast", x
= as.double(x), nrow = as.integer(nrow(x)), ncolx = as.integer(ncol(x)), : ! "corFast" not available for .C() for
package "MRMRF Error in .local(conn, statement, ...) : Unable to
execute statement 'SELECT * FROM cor_test();'. Server says '!Error
running R expression. Error message: Error in .C("corFast", x =
as.double(x), nrow = as.integer(nrow(x)), ncolx = as.integer(ncol(x)),
: '.
Yes this is a known issue where only the first line of the error message is returned. We should fix this. I always use stop(whatever) to return some info from within the UDF.