Hello I'm a new in R I have a large data.frame "s" (this is actualy just a table in mysql) :> names(s)[1] "symbols", "day", "value" I need to convert it to simple matrix. I have define this matrix like this:> data.matrix <- matrix(nrow=nDays, ncol=nSymbols, dimnames=list(days,symbols)) then i just copy values to the matrix using for() loop, but it seems to take very long time. Is is a more fast way to do it in R? I know, what i can just gyve s$value as source data to the matrix, but problem is, what for some symbols couple days could be just missed. Cheers, Dima [[alternative HTML version deleted]]
Can't you just convert you df as follow matrix <- as.matrix(s) ? Double check it as I am a newbie too. :-) Regards, Alberto On 4 March 2011 06:08, Dmitrij Kudriavcev <dimitrij.kudriavcev@ntsg.lt>wrote:> Hello > > I'm a new in R > I have a large data.frame "s" (this is actualy just a table in mysql) : > > > names(s) > [1] "symbols", "day", "value" > > I need to convert it to simple matrix. I have define this matrix like this: > > > data.matrix <- matrix(nrow=nDays, ncol=nSymbols, dimnames=list(days, > symbols)) > > then i just copy values to the matrix using for() loop, but it seems to > take > very long time. Is is a more fast way to do it in R? I know, what i can > just > gyve s$value as source data to the matrix, but problem is, what for some > symbols couple days could be just missed. > > Cheers, > Dima > > [[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. >[[alternative HTML version deleted]]
Hi, Let's say your data.frame is called df: df <- data.frame(a=rnorm(10), b=rnorm(10)) data.matrix <- as.matrix(df) This should work, but be careful with coercion if you have different modes in your data.frame HTH, Ivan PS: next time, provide a reproducible example, using dput() for example Le 3/4/2011 07:08, Dmitrij Kudriavcev a ?crit :> Hello > > I'm a new in R > I have a large data.frame "s" (this is actualy just a table in mysql) : > >> names(s) > [1] "symbols", "day", "value" > > I need to convert it to simple matrix. I have define this matrix like this: > >> data.matrix<- matrix(nrow=nDays, ncol=nSymbols, dimnames=list(days, > symbols)) > > then i just copy values to the matrix using for() loop, but it seems to take > very long time. Is is a more fast way to do it in R? I know, what i can just > gyve s$value as source data to the matrix, but problem is, what for some > symbols couple days could be just missed. > > Cheers, > Dima > > [[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. >-- Ivan CALANDRA PhD Student University of Hamburg Biozentrum Grindel und Zoologisches Museum Abt. S?ugetiere Martin-Luther-King-Platz 3 D-20146 Hamburg, GERMANY +49(0)40 42838 6231 ivan.calandra at uni-hamburg.de ********** http://www.for771.uni-bonn.de http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php