Just to echo Allan's request -- I think many of us data.table users do
work interactively at times, so the default `:=` print behavior can be a
problem with large tables.
What would be the cons of using a default print behavior for `:=` that
only prints top and last `n` rows as in data.table:::print.data.table ?
--Mel.
On 9/13/2012 5:41 PM, Steve Lianoglou wrote:
Hi,
On Thu, Sep 13, 2012 at 5:16 PM, Allan Engelhardt <[email protected]> wrote:
Is there any way of tuning off the printing when using the := assignment? I
have taken to writing code like
library("data.table")
DT <- data.table(idx = 1:10, key = "idx")
for (i in 1) { # Avoid default print
DT[, v := runif(idx)]
}
just to avoid cluttering my screen. I could of course wrap it in invisible()
instead, though I am not sure that makes for much cleaner code, or use
DT$v <- with(DT, runif(idx))
when adding new columns. But I thought := was clever and used an
overallocation trick, and I of course wanted to benefit from this.
This has come up in the past, see:
https://r-forge.r-project.org/tracker/index.php?func=detail&aid=2128&group_id=240&atid=978
Which also links you here for some ideas on how to get around it:
http://stackoverflow.com/questions/11359553/how-to-suppress-output-when-using-in-r-data-table
But, doesn't this only bite you when you are working interactively? If
the call to `:=` is inside a function or script, then the output won't
be printed, so ... does that mean you're writing these for() loops
during an interactive session? (¡ouch!).
For the interactive session, perhaps your easiest "fix" (for now) is
to reassign [, := ...] back to itself, or to a one-letter dummy var
HTH,
-steve
_______________________________________________
datatable-help mailing list
[email protected]
https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
