On Sep 11, 2009, at 12:15 PM, carol white wrote:
Hi,
It might be a primitive question but how it is possible to determine
if a variable is initialized in an environment? Suppose that we
start a R session and wants to run a script which use the variable
i. Which function could evaluate if i is already initialized or not
and if not, then ask interactively the user to set it? This is to
avoid the error message: object i is not found.
Regards,
Carol
See ?exists
Note that this will tell you if the object exists, not if it contains
a specifically desired initial value. You would have to check for the
latter after determining that the object does indeed exist.
HTH,
Marc Schwartz
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
