Error in file(filename, "r", encoding = encoding) : cannot open the connection

Question

I have an RScript file (let's call it main.r) which has a reference to another file, using the below code:

source("functions.R")

But, when I run the RScript file, it complains with the below error:

    Error in file(filename, "r", encoding = encoding) : 
      cannot open the connection
    In addition: Warning message:
    In file(filename, "r", encoding = encoding) :
      cannot open file 'functions.R': No such file or directory

I am sure, my main.R file is next to functions.R in the same directory. I can call the functions.R in the Rmd (RMarkdown) file which exist in the same directory

Answer 1

In your case try to add setwd("path/to/project/") in main.R where path/to/project/ contains main.R.

Then you can source functions.R either directly by source("functions.R") if both files lie in the same directory or source("sub-folder/functions.R") if the latter file is contained in a sub-folder.

If you're not working on a RStudio project, chances are the working directory of main.R might be your home directory.

Answer 2

If the file you source ALSO uses source("...") to reference other files, you will get this same error.

For example:

1. Your working directory is getwd() ".../projectA"
2. You have another file you want to reference from another R Project called functions.R. So you try to source this source(".../projectB/functions.R"). This results in the error.
3. It's because contained in the code of functions.R is source("helper_functions.R"). But your source is using the original path (e.g., .../projectA/), not the project path of functions.R (e.g., .../projectB/)