R help - Sep 2003 - using assign on save?

I have an object which I want to save into an external file, using save, on a
time step in loop. In the loop I have an if statment that will save when the
appropraite time, t, is reached.

I want to change the object and the name of the saved object to reflect which
time step is being written. I can do the file name in save using paste but
cannot rename the object.

For example, I want to save object foo at time t = 50 in file
"Run.50.Rdata." Furthermore, I want the object in that file to be
"foo50."

This is what I'm doing now:

    save(foo, file = paste("Run", t,
"Rdata",sep="."))

which creates the right file name but obviously doesn't rename the object.

So, I tried assigning the object in the save function.

  save(assign(paste("foo", t, sep = ""), foo),
       file = paste("Run", t, "Rdata",sep="."))

This crashes. It would also leave a copy of foo50 in the workspace which is
messy.

The logic of how to rename the object at a time step, reference it in the save
statement and then remove it is eluding me.

Any thoughts on how to proceed?

-Andy

Andy  -

help("assign")  says:

"Value:  This function is invoked for its side effect, which is
assigning `value' to the variable `x'.  ..."

Gosh.  The help page isn't very specific about what the return
value of  assign()  IS, but it's not a named object.  Your basic
strategy of assigning, writing, then removing sounds like a good
one, but perhaps these have to be three separate lines inside the
loop.  If that's so, then it's worth making a temporary character
string variable with the result of  paste(), so you can use it
three times.  Think also about where the assignment is going to
take place.

Warning: I haven't tried out any of the suggestions I am making.

HTH  -  tom blackwell  -  u michigan medical school  -  ann arbor  -

On Wed, 24 Sep 2003, Andy Bunn wrote:
> I have an object which I want to save into an external file, using save, on
a time step in loop. In the loop I have an if statment that will save when the
appropraite time, t, is reached.
>
> I want to change the object and the name of the saved object to reflect
which time step is being written. I can do the file name in save using paste but
cannot rename the object.
>
> For example, I want to save object foo at time t = 50 in file
"Run.50.Rdata." Furthermore, I want the object in that file to be
"foo50."
>
> This is what I'm doing now:
>
>     save(foo, file = paste("Run", t,
"Rdata",sep="."))
>
> which creates the right file name but obviously doesn't rename the
object.
>
> So, I tried assigning the object in the save function.
>
>   save(assign(paste("foo", t, sep = ""), foo),
>        file = paste("Run", t,
"Rdata",sep="."))
>
> This crashes. It would also leave a copy of foo50 in the workspace which is
messy.
>
> The logic of how to rename the object at a time step, reference it in the
save statement and then remove it is eluding me.
>
> Any thoughts on how to proceed?
>
> -Andy