[R] How to get commands history as a character vector instead of displaying them?

[Romain Francois]

Yihui Xie wrote:
> Hi Everyone,
>
> I want to get the commands history as a character vector instead of
> just displaying them, but the function history() just returns NULL. I
> checked the source code of 'history' and could not find a solution.
> Anybody has an idea? Thanks!
>   
history eventually calls file.show, which will use the pager option to 
determine how to show the file, so you can do something like that:

history <- function( ... ){
old.op <- options( pager = function( files, header, title, delete.file ) 
readLines( files ) ); on.exit( options( old.op ) )
utils::history(...)
}
history( pattern = "png" )

I don't see a way to get device information other than the name of the 
device (with dev.cur)

Romain

> P. S. My original problem is, when a user opens a graphics device like
> png() or pdf(), I want to know the file name used by this device. I
> thought history() would help, but it could not.
>
>   
>> sessionInfo()
>>     
> R version 2.8.1 (2008-12-22)
> i386-pc-mingw32
>
> locale:
> LC_COLLATE=Chinese_People's Republic of
> China.936;LC_CTYPE=Chinese_People's Republic of
> China.936;LC_MONETARY=Chinese_People's Republic of
> China.936;LC_NUMERIC=C;LC_TIME=Chinese_People's Republic of China.936
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
> Regards,
> Yihui
> --
> Yihui Xie <xieyihui at gmail.com>
> Phone: +86-(0)10-82509086 Fax: +86-(0)10-82509086
> Mobile: +86-15810805877
> Homepage: http://www.yihui.name
> School of Statistics, Room 1037, Mingde Main Building,
> Renmin University of China, Beijing, 100872, China
>
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>
>
>   


-- 
Romain Francois
Independent R Consultant
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr