This is a basic r file access error, when you are trying to open data files and R can’t find the file. The part of the error message “error in file(file, “rt”)” indicates the failure is with the low level function used to open a specific excel file or r code file at a location. R is trying to open a data file and can’t find a file to open at the folder location that you specified or with the correct extension (a common csv file error. Which explains the “cannot open the connection” portion of the error message.
You can trigger this error through any R code file system problem that results in a bad file path reference. However, this is generally a problem with how you are referring to your working directory. You can check the working directory using the getwd() command.
Fixing the Bug
This is going to require some debugging. The specifics of this R programming error may vary slightly depending on what R version or R package you are using, what exactly the missing value is, and the exact command you used – but your R code is essentially telling you it cannot find the file:
- This is most likely an issue with how you’re referring to your current working directory. Use the getwd() function to assess what the R program views as the current working directory. You could be dealing with an old default setting in your local environment. If the working directory isn’t what you expected, you have two options. To fix it for the current session, use the setwd() command. Alternatively, you can specify the exact file name directly in your R code once you have set the working directory properly.
- It is possible you are having issues with relative R file references to directories above and below the current working directory. Remember to use “../” for files in the parent directory.
- You could also be having issues with data file suffixes. Inspect your exact file text handles using Windows.
- If you are using a remote server drive, test the download.
- Reaching a bit here, but watch for character string errors (and check your backslashes) if you’re passing your input files names as a variable.
- R can get cranky about connectivity with excel files; check your package settings. Comma delimited and text files should be more or less native to R.
- This is most likely not a header issue. This is a file system issue and occurs before readlines() actually has a chance to execute against the file. (which means it would also not be related to issues such as a errors in defining your character variables, array or vector logic, and various examples of byte level encoding issues).
See our article on using setwd() to set the working directory properly.
Common Errors & Warning Message
As R errors go, this isn’t a bad one. It tends to announce itself quickly and is easily solved once you understand where the working directory setting is pointed. This can be a bit tricky on a Window(s) system, since the active working directory of the R environment may differ from the working directory of the script or output file. Unlike most data frame errors, there is little risk of corrupting your analysis & insights.
For some reason, I tend to have this issue more with csv file(s) and MS Access databases. This is especially true on a Window(s) system. So check the file path for the csv files carefully and be very careful of relative references.
If you still have any question(s) about solving this error, free free to leave a comment below and our team will look into it…