Thanks a lot for your response Peter, > I've not used these libraries, but one important question is are you familiar > with both R and python?
No, i'm beginer... but i need to learn this two technology this summer, because this is the student job (geography/computer science student) :-]] import rpy rpy.set_default_mode(rpy.NO_ > > CONVERSION) > #your code here: > rpy.r.library("Rdbi") > rpy.r.library("RdbiPgSQL") > rpy.r.dbConnect(rpy.r.PgSQL(),host="localhost", dbname="simpop", > user="postgres", password="postgres") > #If you want to go back to the default conversion, > rpy.set_default_mode(rpy.BASIC_CONVERSION) > Connection is ok with this code, thanks a lot to help me ! Seb On Thu, Jun 25, 2009 at 3:20 PM, Peter <rpy-l...@maubp.freeserve.co.uk>wrote: > On Thu, Jun 25, 2009 at 2:08 PM, reyman<reyma...@gmail.com> wrote: > > Hello guys, > > > > I have a big project for six month, i need a little help about technology > > imbrication ... > > > > 1) Reflexion about System architecture > > > a) I want to make script in python which control/launch R, R access > > data with library "rdbi" and "RdbiPgSQL". I need this to realize simple > > statistics. Do you think it's better to access data in DB with R or with > > python in this case ? > > > b) I want in near futur to create an another type of script wich > > access data in DB with grass by R module "spgrass6" (wich interface R > <--> > > GRASS). I need this to make Spatial Analysis > > > > So with my two type of script a) and b) , you think Rpy is a good choice > to > > manipulate data/query in R and R <-> GRASS ? Have you an experience in > this > > type of plateform/architecture? > > I've not used these libraries, but one important question is are you > familiar > with both R and python? > > > 2) I have problem with RPY and connexion with my DB : > > > > from rpy import * > > import math > > > > r.library("Rdbi") > > r.library("RdbiPgSQL") > > > > r.dbConnect(r.PgSQL(),host="localhost", dbname="simpop", user="postgres", > > password="postgres") > > > > I have this error message : > > > > Traceback (most recent call last): > > ... > > Invalid database class > > > > In R, with the same query, no error ... > > That is almost certainly due to the default object conversion, the > most common cause of confusion in rpy beginners. > > rPgSQL() returns some database class, which rpy has converted into a > simplified representation using python objects. You then try and pass > this back to the r.dbConnect, which means rpy has to try and turn this > simplified python structure back into R objects. I don't know exactly > what this will look like (maybe an R list), but > it won't be a database object! > > You should turn off the conversion. > > Try something like this: > > import rpy > rpy.set_default_mode(rpy.NO_CONVERSION) > #your code here: > rpy.r.library("Rdbi") > rpy.r.library("RdbiPgSQL") > rpy.r.dbConnect(rpy.r.PgSQL(),host="localhost", dbname="simpop", > user="postgres", password="postgres") > #If you want to go back to the default conversion, > rpy.set_default_mode(rpy.BASIC_CONVERSION) > > Peter > > > ------------------------------------------------------------------------------ > _______________________________________________ > rpy-list mailing list > rpy-list@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/rpy-list >
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