Reading Online and Local Data Files in Rmarkdown, Bookdown, or Blogdown

Hongtao Hao / 2020-08-24



Here is a tutorial on how to read local data files in Rmarkdown. I found it very helpful. Nonetheless, I decided to write on this topic again myself because that post is a bit more complicated than it should be.

We can read data files from two sources: online, or local.

Reading Online Files

Reading online files is easy:

library(readr)
hello  <- read_csv("https://hongtaoh.com/files/HGN.csv")

Reading Local Files

To read local files in Rmarkdown, you can either specify the exact paths, or use the package of here. One thing worth noticing is that R can read any local files, either they are in the same root directory as your Rmarkdown file or not, as long as you correctly specify the exact paths. However, if you use the package of here, the data files to be read must be in the same directory as your Rmarkdown file.

Files in a different directory

No matter where your local data file is located, you can simply specify its full path, and it should always work:

hello <- read_csv("/full/path/to/your/file/filename.csv")

Note that the file does not have to be in a csv format. It can be an Excel or anything that R can read.

How to find a file’s full path then?

I assume you are using a Mac: Right click the data file, click on Get Info, and then you can find it in Where. Simply copy and past that path. Don’t forget to add the forename to the end. For example, if you have a data file called filename.csv, the path you can find in Where is only /full/path/to/your/file/, you should add filename.csv to the end by yourself.

Files in a the same directory

Relative path WITHOUT using here

I tried the ../../ method mentioned in the blog post above but it simply gave me an Error, at least on Blogdown.

For example, suppose you have a folder named Project on your Desktop, and the location of your data file relative to your Blogdown project or Rmd is this:

|____Folder_1
|____Folder_2
|____Static
| |____Data
| | |____YourData.csv
|____YourBlogdownProj.RProj

Then using AGoodName <- read_csv( "../../Static/Data/YourData.csv") won’t work the way the blog post mentioned.

Then how to solve this problem?

  • Simply use the full path using the method I gave above: /Users/YourMacUserName/Desktop/Project/Static/Data/YourData.csv

  • Use the here package, if you are lazy.

Relative path using here

Simply use this:

library(here)
AGoodNmae <- read_csv(here("Static", "Data", "YourData.csv"))

You can find more information about the here package from the blog post or this thread.

Last modified on 2020-08-31