[R] save(), load(), saveRDS(), and readRDS()

[Shu Fai Cheung]

Hi All,

There is a thread about the use of save(), load(), saveRDS(), and
loadRDS(). It led me to think about a question regarding them.

In my personal work, I prefer using saveRDS() and loadRDS() as I don't like
the risk of overwriting anything in the global environment. I also like the
freedom to name an object when reading it from a file.

However, for teaching, I have to teach save() and load() because, in my
discipline, it is common for researchers to share their datasets on the
internet using the format saved by save(), and so students need to know how
to use load() and what will happen when using it. Actually, I can't recall
encountering datasets shared by the .rds format. I have been wondering why
save() was usually used in that case.

That discussion led me to read the help pages again and I noticed the
following warning, from the help page of saveRDS():

"Files produced by saveRDS (or serialize to a file connection) are not
suitable as an interchange format between machines, for example to download
from a website. The files produced by save
<http://127.0.0.1:18888/library/base/help/save> have a header identifying
the file type and so are better protected against erroneous use."

When will the problem mentioned in the warning occur? That is, when will a
file saved by saveRDS() not be read correctly? Saved in Linux and then read
in Windows? Is it possible to create a reproducible error?

Regards,
Shu Fai

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