R help - Apr 2014 - Lazy loading of CSV file

Hi, in a package I am developing some functions need to use some external
data.
I have these data as a set of .csv files that I have placed in the
inst/extdata folder.

At the moment I have a file "db-internal.r" where I  load all the
internal
databases that could be used by the functions in my package;
and assign them to some global (to the package) variables (all with the
prefix db_ in front of them)
For example (I didn't come out with a better name, sorry)

db_italian_cities = read.csv(system.file("extdata/italian_cities.csv")

like this I can use db_italian_cities in my functions.

Some of these datasets are quite big and really slow down loading the
package, plus for some of the task the package is meant to solve they might
not even be required.
I would like to be able to lazyload these datasets only when needed, how
can I possibly achieve this without creating special databases?

Some of them could change, so I intend to be able to download the most
recent ones through a function that ensure the package is using the most
recent version,
so I would really prefer to simply use csv files.

Thanks a lot in advance for the help!

Cheers,
Luca

	[[alternative HTML version deleted]]

The standard way to put data into a package is to convert it to RDA as described
in the Writing R Extensions document. This is faster and more compact than CSV.
---------------------------------------------------------------------------
Jeff Newmiller                        The     .....       .....  Go Live...
DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live
Go...
                                      Live:   OO#.. Dead: OO#..  Playing
Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
/Software/Embedded Controllers)               .OO#.       .OO#.  rocks...1k
--------------------------------------------------------------------------- 
Sent from my phone. Please excuse my brevity.

On April 16, 2014 5:10:03 AM PDT, Luca Cerone <luca.cerone at gmail.com>
wrote:
>Hi, in a package I am developing some functions need to use some
>external
>data.
>I have these data as a set of .csv files that I have placed in the
>inst/extdata folder.
>
>At the moment I have a file "db-internal.r" where I  load all the
>internal
>databases that could be used by the functions in my package;
>and assign them to some global (to the package) variables (all with the
>prefix db_ in front of them)
>For example (I didn't come out with a better name, sorry)
>
>db_italian_cities =
read.csv(system.file("extdata/italian_cities.csv")
>
>like this I can use db_italian_cities in my functions.
>
>Some of these datasets are quite big and really slow down loading the
>package, plus for some of the task the package is meant to solve they
>might
>not even be required.
>I would like to be able to lazyload these datasets only when needed,
>how
>can I possibly achieve this without creating special databases?
>
>Some of them could change, so I intend to be able to download the most
>recent ones through a function that ensure the package is using the
>most
>recent version,
>so I would really prefer to simply use csv files.
>
>Thanks a lot in advance for the help!
>
>Cheers,
>Luca
>
>	[[alternative HTML version deleted]]
>
>______________________________________________
>R-help at r-project.org mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.