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require(..., quietly=TRUE) does not suppress warning

4 messages · Dan Tenenbaum, John Nolan, Kevin Ushey

Original
Dan Tenenbaum
# 
Hi,

The `quietly` argument of `require` is documented as follows:

 quietly: a logical.  If ?TRUE?, no message confirming package
          attaching is printed, and most often, no errors/warnings are
          printed if package attaching fails.

However:
Warning message:
In library(package, lib.loc = lib.loc, character.only = TRUE, logical.return = TRUE,  :
  there is no package called ?foo?

Am I misreading the docs or is R misbehaving?
R version 3.3.2 (2016-10-31)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: macOS Sierra 10.12.1

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

Dan
John Nolan
# 
Well, it says "most often" no errors/warnings are given, so it is not contradicting the docs!   It looks like the person/team that coded  require( ) decided you should get an error when the package doesn't exist.

If you want a silent loading, consider
     aaa <- try( library(foo,verbose=FALSE,quietly=TRUE),silent=TRUE)
and then check to see if aaa is of class "try-error" and check for failure

John
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John P. Nolan
Math/Stat Dept., American University
Gray Hall, 4400 Massachusetts Ave, NW
Washington, DC 20016-8050
Phone: 202-885-3140
E-mail:  jpnolan at american.edu
Web:   http://fs2.american.edu/jpnolan/www/



-----Original Message----
From: R-devel [mailto:r-devel-bounces at r-project.org] On Behalf Of Dan Tenenbaum
Sent: Thursday, December 8, 2016 2:43 PM
To: R-devel <r-devel at r-project.org>
Subject: [Rd] require(..., quietly=TRUE) does not suppress warning

Hi,

The `quietly` argument of `require` is documented as follows:

 quietly: a logical.  If ?TRUE?, no message confirming package
          attaching is printed, and most often, no errors/warnings are
          printed if package attaching fails.

However:
Warning message:
In library(package, lib.loc = lib.loc, character.only = TRUE, logical.return = TRUE,  :
  there is no package called ?foo?

Am I misreading the docs or is R misbehaving?
R version 3.3.2 (2016-10-31)
Platform: x86_64-apple-darwin13.4.0 (64-bit) Running under: macOS Sierra 10.12.1

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

Dan

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https://stat.ethz.ch/mailman/listinfo/r-devel
Dan Tenenbaum
# 
Well, I'm getting a warning (not an error) when the package doesn't exist.
I interpreted "most often" to mean that suppressing warnings/errors is why you'd most often use this argument, as most packages don't emit startup messages. 

And technically there isn't a problem with attaching the package, since we don't even try to attach packages that don't exist.

So yes, very careful parsing of the docs suggests that the behavior is correct, but it does seem to violate the 'spirit' of what a user might expect. I am pretty sure I have used the 'if (!require("pkg")) install.packages("pkg")' pattern before without seeing this warning, so I wondered if the behavior had changed, and that's what prompted me to write.

I know I can squelch the warning by wrapping the require() in suppressWarnings(). 

Dan


----- Original Message -----
Kevin Ushey
# 
IMHO the strongest argument for suppressing the warning message here is the
fact that

    requireNamespace("foo", quietly = TRUE)

does not emit any warning message when the package 'foo' does not exist.

On Thu, Dec 8, 2016 at 12:51 PM, Dan Tenenbaum <dtenenba at fredhutch.org>
wrote: