On Thu, Jun 25, 2009 at 9:40 AM, reyman <reyma...@gmail.com> wrote: > 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) :-]] >
Have you considered using only R or python (and not both)? You also might want to look at using pl/R from within postgres. Mixing database access, R, and python in such ways can be done, but there are alternatives. Sean > > > 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 >> > > > > > ------------------------------------------------------------------------------ > > _______________________________________________ > rpy-list mailing list > rpy-list@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/rpy-list > >
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