[R] What is the fastest way to see what are in an RData file?

[Peng Yu]

On Thu, Dec 17, 2009 at 5:33 AM, Gustaf Rydevik
<gustaf.rydevik at gmail.com> wrote:
> On Wed, Dec 16, 2009 at 10:13 PM, Peng Yu <pengyu.ut at gmail.com> wrote:
>>
>> Currently, I load the RData file then ls() and str(). But loading the file
>> takes too long if the file is big. Most of the time, I only interested what
>> the variables are in the the file and the attributes of the variables (like
>> if it is a data.frame, matrix, what are the colnames/rownames, etc.)
>>
>> I'm wondering if there is any facility in R to help me avoid loading the
>> whole file.
>
>
> I thought this was interesting as well, so i did a bit of searching
> through the R-help list archives and found this answer by Simon
> Urbanek:
> https://stat.ethz.ch/pipermail/r-devel/2007-August/046724.html
> The link to a c-routine that does what you want still works, but for
> future reference I'm pasting the code below.

It doesn't work for the RData file that I saved by "save(list='test',
file='test.RData')".

$ rdcopy test.RData
Format version 3ec, R version = 23813.88.84, release = f9db1dba
Sorry, this tool supported RXDR version 2 format only