[R] reaccessing array at a later date - trying to write it to file

[Jenny Barnes]

Thank you Barry for your time in responding!

I think that will really help - the difference between attach and load were not 
clear to me before your reply! Also I did not know about rm() - thank you for 
the detail, I know you took longer than you had planned but I do appreciate it,

For those with a similar problems in the future please see the responses below:

>
>Jenny Barnes wrote:
>
>> Having tried again your suggestion of load() worked (well - it finished, 
which I 
>> assume it meant it worked). However not I am confused as to how I can check 
it 
>> has worked. 
>> I typed
>> 
>>>data.out$data
>> 
>> which called up the data from the file - but I'm not sure if this is data 
from 
>> the file I have just restored as in my "previously saved workspace restored" 
>
>  Remove it from your current workspace:
>
>  > rm(data.out)
>
>  then do the load('whatever') again:
>
>  > load("/some/path/to/data.out.RData")
>
>  then see if its magically re-appeared in your workspace:
>
>  > data.out$data
>
>  But now if you quit and save your workspace it'll be in your workspace 
>again when you start up.
>
>  So you could consider 'attach' instead of 'load'...
>
>  Remove data.out from your current workspace, save your current 
>workspace (with 'save()' - just like that with nothing in the 
>parentheses), then instead of load('/some/path/to/data.out.RData') use:
>
>  > attach('/some/path/to/data.out.RData')
>
>  This makes R search for an object called 'data.out' in that file 
>whenever you type 'data.out'. It will find it as long as there's not a 
>thing called 'data.out' in your workspace. So if you do attach(...) and 
>then do:
>
>  > str(data.out)
>
>  you'll see info about your data.out object, but then do:
>
>  > data.out=99
>  > str(data.out)
>
>  you'll see info about '99'. Your data.out is still happily sitting in 
>its .RData file, its just masked by the data.out we created and set to 
>99. Delete that, and your data.out comes back:
>
>  > rm(data.out)
>  > str(data.out) # - your data object again
>
>  The advantage of this is that data.out wont be stored in your current 
>workspace again. The disadvantage is that you have to do 
>'attach(...whatever...)' when you start R, and that data.out can be 
>masked if you create something with that name in your workspace. It is a 
>handy thing to do if you create large data objects that aren't going to 
>change much.
>
>>  Also, is it normal that if I type 
>> 
>>>data.out.RData
>> 
>> it says
>> Error: object "data.out.RData" not found
>
>  Yes, because thats the name of the _file_ on your computer and not the 
>R object.
>
>  This should be in the R manuals and help files... and I've gone on 
>much longer than I intended to in this email :)
>
>Barry

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jennifer Barnes
PhD student - long range drought prediction
Climate Extremes
Department of Space and Climate Physics
University College London
Holmbury St Mary, Dorking
Surrey
RH5 6NT
01483 204149
07916 139187
Web: http://climate.mssl.ucl.ac.uk