R SIG Debian - Mar 2017 - Package selectr: issue with the apt-get version, but not with the one installed from R?

Hi

I am facing an issue with the package selectr, where I get an error trying
to run an example code: css_to_xpath(".testclass"), gives could not
find
function "xpath_class"

The issue arises however only with the package installed with apt-get, not
when installed from within R. I got a similar issue with maptools, where I
was not able to use data(wrld_map), and switching to the version "from
within R" version did solve the issue in the same way.

Note that I posted the issue some time ago on stack-overflow:
http://stackoverflow.com/questions/40874011/r-rvest-could-not-find-function-xpath-element/42960170#42960170
but now that I pinned the issue down to the apt-get versus R, I hope I can
ask on this list?  For the apt-get, I have cran sources added, as well as
Michael's ppa http://ppa.launchpad.net/marutter/rrutter/ubuntu and
http://ppa.launchpad.net/marutter/c2d4u/ubuntu

Here is a sample code showing my issue:
> pkg <- installed.packages()
> subset(as.data.frame(pkg), Package=="selectr",
c("Package", "LibPath"))
          Package                                         LibPath
selectr   selectr /home/matifou/R/x86_64-pc-linux-gnu-library/3.3
selectr.1 selectr                        
/usr/lib/R/site-library
> library(selectr,
lib.loc="/home/matifou/R/x86_64-pc-linux-gnu-library/3.3")
> css_to_xpath(".testclass")
[1] "descendant-or-self::*[@class and contains(concat(' ',
normalize-space(@class), ' '), ' testclass
')]"
> detach("package:selectr", unload=TRUE)
> library(selectr, lib.loc="/usr/lib/R/site-library")
> css_to_xpath(".testclass")
Error in do.call(method, list(parsed_selector)) :
  could not find function "xpath_class"

Thanks!!

Matthieu

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On 03/22/2017 02:54 PM, Matthieu S wrote:
> Hi
>
> I am facing an issue with the package selectr, where I get an error trying
> to run an example code: css_to_xpath(".testclass"), gives could
not find
> function "xpath_class"
>
> The issue arises however only with the package installed with apt-get, not
> when installed from within R. I got a similar issue with maptools, where I
> was not able to use data(wrld_map), and switching to the version "from
> within R" version did solve the issue in the same way.
>
> Note that I posted the issue some time ago on stack-overflow:
>
http://stackoverflow.com/questions/40874011/r-rvest-could-not-find-function-xpath-element/42960170#42960170
> but now that I pinned the issue down to the apt-get versus R, I hope I can
> ask on this list?  For the apt-get, I have cran sources added, as well as
> Michael's ppa http://ppa.launchpad.net/marutter/rrutter/ubuntu and
> http://ppa.launchpad.net/marutter/c2d4u/ubuntu
Matthieu,

I am able to recreate this, but I am not sure what the solution is.  I 
am going to try a couple of things and let you know.  The code for 
"xpath_class" is there, it is just not finding it.

Thanks for pointing this out,
Michael
>
> Here is a sample code showing my issue:
>
>> pkg <- installed.packages()
>> subset(as.data.frame(pkg), Package=="selectr",
c("Package", "LibPath"))
>           Package                                         LibPath
> selectr   selectr /home/matifou/R/x86_64-pc-linux-gnu-library/3.3
> selectr.1 selectr                         /usr/lib/R/site-library
>> library(selectr,
> lib.loc="/home/matifou/R/x86_64-pc-linux-gnu-library/3.3")
>> css_to_xpath(".testclass")
> [1] "descendant-or-self::*[@class and contains(concat(' ',
> normalize-space(@class), ' '), ' testclass ')]"
>> detach("package:selectr", unload=TRUE)
>> library(selectr, lib.loc="/usr/lib/R/site-library")
>> css_to_xpath(".testclass")
> Error in do.call(method, list(parsed_selector)) :
>   could not find function "xpath_class"
>
> Thanks!!
>
> Matthieu
>
> 	[[alternative HTML version deleted]]
>
> _______________________________________________
> R-SIG-Debian mailing list
> R-SIG-Debian at r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-debian
>

On 03/22/2017 02:54 PM, Matthieu S wrote:
> Hi
>
> I am facing an issue with the package selectr, where I get an error trying
> to run an example code: css_to_xpath(".testclass"), gives could
not find
> function "xpath_class"
>
> The issue arises however only with the package installed with apt-get, not
> when installed from within R. I got a similar issue with maptools, where I
> was not able to use data(wrld_map), and switching to the version "from
> within R" version did solve the issue in the same way.
>
> Note that I posted the issue some time ago on stack-overflow:
>
http://stackoverflow.com/questions/40874011/r-rvest-could-not-find-function-xpath-element/42960170#42960170
> but now that I pinned the issue down to the apt-get versus R, I hope I can
> ask on this list?  For the apt-get, I have cran sources added, as well as
> Michael's ppa http://ppa.launchpad.net/marutter/rrutter/ubuntu and
> http://ppa.launchpad.net/marutter/c2d4u/ubuntu
>
Matthieu,

A new version of r-cran-selectr is on the PPA.  I think it fixes the 
issue you had.  Not sure if it is correct, but I am getting a different 
result that does not appear to be an error.

Turns out that there is a dependency on codetools that is not listed on 
CRAN.  This is why your local version (which likely has codetools 
installed) worked and not the one built on the PPA.  But that has been 
fixed, and will be for all future versions.

Michael