From b.rowlingson at lancaster.ac.uk  Sun Dec 18 02:32:52 2011
From: b.rowlingson at lancaster.ac.uk (Barry Rowlingson)
Date: Sun, 18 Dec 2011 01:32:52 +0000
Subject: [Rd] Saving nothing with save()
Message-ID: <CANVKczNM=0L+8RbN_rwfG898euRu9y-jFUdgWtQ9RRZk1h71-w@mail.gmail.com>

Scenario: Here I am working away in R. I've got results that prove
global warming is anthropogenic and also the solution for producing
limitless carbon-neutral energy from nuclear fusion. Its been a good
day.

So, I want to save my work. I don't want to overwrite my current
.RData, so I save it to another file:

save(file="prize.RData")  # just need to email this to the Nobel committee
q()
  Save workspace image? [y/n/c]: - "no" I don't want to save the
workspace image, I just saved everything to "prize.RData". But gee, it
did seem to do that quite quickly considering the volume of evidential
data in my work. My unix shell prompt returns.

Uh oh. See what I did there? I typed 'save' when I meant 'save.image'.
What does that give me?

 A 42 byte, empty, latest.RData, and because there was no warning or
error I quit without saving it again. Oops. Massive Data Loss.

 Is there any reason why save(file="file.RData") couldn't warn or
error if you try and save nothing? There's no obvious check in the R
code for save.

Barry

PS the above scenario is fictional. When did I last have a good day?



[Rd] Saving nothing with save()
Barry Rowlingson