[R] How to create ff objects from database connection
Hi Does anybody know how to create ff objects with data reading from stream objects, such as data reading from PostgreSQL database through RPostgreSQL. For this purpose although we can save the data to a csv file through external tools and then read it through csv readers, but it requires one more data read and write operation, which is of high I/O cost for large datasets. Xiaobo.Gu [[alternative HTML version deleted]] __ R-help@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.
[R] Package ff and parallel processing
Hi, After reading the slices from ff project site I know ff can be used with snowfall to achieve parallel processing, I want to know is it the only way, can we combine package foreach and ff, especially in a SMP server, with doMC and multicore behind foreach. Xiaobo.Gu [[alternative HTML version deleted]] __ R-help@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.
[R] ff objects and ordinary analytical functions.
Hi, Can the plenty of analytical functions provided by base R and contributed packages be called with ff objects as parameters directly, or do we have to write special version of the functions for ff objects? If it is the latter case, is there a list of functions which support ff objects already. Xiaobo.Gu [[alternative HTML version deleted]] __ R-help@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.
[R] Can saved R object .RData files be loaded by more than one R sessions for read only purpose?
Especially for large ff objects. Xiaobo.Gu [[alternative HTML version deleted]] __ R-help@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.
[R] some questions about rattle.
Hi, Can rattle utilize parallel processing mechanisms such as foreach? Can rattle analyze ff objects ? Xiaobo.Gu [[alternative HTML version deleted]] __ R-help@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.
Re: [R] Ways to work with R and Postgres
Hi Gabor,
The package dependency path is RpgSQL- RJDBC - rJava, but it seems this is
not a Windows 64bit rJava package.
Regards.
Xiaobo.Gu
-Original Message-
From: Gabor Grothendieck [mailto:ggrothendi...@gmail.com]
Sent: Sunday, June 27, 2010 12:51 PM
To: 顾小波
Cc: r-help@r-project.org
Subject: Re: [R] Ways to work with R and Postgres
2010/6/27 顾小波 guxiaobo1...@gmail.com:
Hi,
I post this message to the general r-help list hoping anyone within a wider
range have suggestions:
There are three ways to integration R and postgres, especially on 64bit
Microsoft windows Platform,
1. via RODBC package, which has 32 bit and 64 bit version for windows
2. via RPostgres interface, which only has 32bit version currently
3. via plr for Greenplum, which only supports a few kinds of functionality,
and supports only specific versions of R.
Do you have any idea about the advantages and disadvantages of each, and the
differences among them
There is also the RpgSQL package. In addition the sqldf package uses
RpgSQL. sqldf by default uses SQLite but if the RpgSQL package is
loaded then it defaults to PostgreSQL. Here BOD Is a built in R
data.frame:
library(sqldf)
Loading required package: DBI
Loading required package: RSQLite
Loading required package: RSQLite.extfuns
Loading required package: gsubfn
Loading required package: proto
Loading required package: chron
library(RpgSQL)
Loading required package: RJDBC
BOD
Time demand
118.3
22 10.3
33 19.0
44 16.0
55 15.6
67 19.8
sqldf('select regr_slope(demand, Time) slope,
+ regr_intercept(demand, Time) intercept,
+ corr(demand, Time) corr from BOD')
Loading required package: tcltk
Loading Tcl/Tk interface ... done
slope intercept corr
1 1.721429 8.521429 0.8030693
coef(lm(demand ~ Time, BOD)); cor(BOD$Time, BOD$demand)
(Intercept)Time
8.5214291.721429
[1] 0.8030693
__
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
[R] Ways to work with R and Postgres
Hi, I post this message to the general r-help list hoping anyone within a wider range have suggestions: There are three ways to integration R and postgres, especially on 64bit Microsoft windows Platform, 1. via RODBC package, which has 32 bit and 64 bit version for windows 2. via RPostgres interface, which only has 32bit version currently 3. via plr for Greenplum, which only supports a few kinds of functionality, and supports only specific versions of R. Do you have any idea about the advantages and disadvantages of each, and the differences among them Your sincerely Xiaobo.Gu [[alternative HTML version deleted]] __ R-help@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.
