monitor variable change
One way to implement this functionality is with a task manager callback:
watch <- function(varname) {
old <- get(varname)
changed <- function(...) {
new <- get(varname)
if (!identical(old, new)) {
message(varname, " is now ", new)
old <<- new
}
TRUE
}
invisible(addTaskCallback(changed))
}
a <- 1
watch("a")
a <- 2
Hadley
On Wed, Feb 16, 2011 at 9:38 AM, Alaios <alaios at yahoo.com> wrote:
Dear all I would like to ask you if there is a way in R to monitor in R when a value changes.
Right now I use the sprintf('my variables is %d \n, j) to print the value of the variable.
Is it possible when a 'big' for loop executes to open in a new window to dynamically check only the variable I want to.
If I put all the sprintf statements inside my loop then I get flooded with so many messages that makes it useless.
Best Regards
Alex
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