On 12/11/2015 6:41 PM, Julio Sergio Santana wrote:
I have to store (in a file) an R object that was created with is name as
a string of characters, as follows:
: nn <- "xxx"
: assign(nn, 5)
: xxx
[1] 5
I don't want to store the object nn but the object xxx. I tried the
following two expressions but none of them worked:
: save(get(nn), file="f.RData")
Error in save(get(nn), file = "f.RData") : object ‘get(nn)’ not found
: save(eval(nn), file="f.RData")
Error in save(eval(nn), file = "f.RData") : object ‘eval(nn)’ not
found
I know that both save(xxx, ..), and save("xxx", ..) work, but the fact
is that the string is going to be provided by an user:
: nn <- readline("Your variable->")
and
: save(nn, file="f.RData")
stores the objet nn not xxx
Do you have any comments on this?
I believe
do.call(save, list(as.name(nn), file = "f.RData"))
should do what you want. There are probably other ways, maybe simpler
ones.
If you're interested, the theory here is that do.call() constructs a
call to the first argument, with arguments found by evaluating the
second argument.
Duncan Murdoch
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