facilitate fetching data files stored inside a package?

[rpruim]

From @rpruim on September 3, 2014 23:29

R packages may contain arbitrary documentation files. We have a couple csv files in the mosaic package, for example. These exist on the system, and find.package() can help to construct the path to these files, but that's too much for beginners.

We could provide a utility to construct these paths, a la:

> docFile("OneTrueLove.csv", package="Lock5withR")
[1] "/Library/Frameworks/R.framework/Versions/3.2/Resources/library/Lock5withR/doc/OneTrueLove.csv"

We could also add a package= option to read.file() so that

read.file("OneTrueLove.csv", package="Lock5withR") 

would read the file.

Copied from original issue: ProjectMOSAIC/mosaic#380

[rpruim]

I've gone ahead and implemented this:

docFile("MustangPrice.csv")
[1] "/Library/Frameworks/R.framework/Versions/3.2/Resources/library/mosaic/doc/MustangPrice.csv"

The default package is mosaic, so we could add some examples of various types of files to demonstrate loading them into R. For files that read.file() knows how to handle, we can even do this:

read.file("MustangPrice.csv", package="mosaic") %>% head
  Age Miles Price
1   6   8.5  32.0
2   7  33.0  45.0
3   9  82.8  11.9
4   2   7.0  24.8
5   3  23.0  22.0
6  15 111.0  10.0

[rpruim]

I'll add a couple examples, including one that demos pulling data from a package.