Hello Let's say, my data.frame is
symbol,day,value A, 2010-01-01, 0.8888 A, 2010-01-02, 0.6666 B, 2010-01-01, 0.7777 i need to get matrix as , A, B 2010-01-01, 0.8888, 0.7777 2010-01-02, 0.6666, NA where A and B is columns name and date used as row name I found a way how to do it with tapply function, is it a best way (i will need to do this pretty offen and wish to save some time) Cheers, Dima 2011/3/4 Ivan Calandra <ivan.calan...@uni-hamburg.de> > 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 écrit : > >> 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. >> >> > -- > Ivan CALANDRA > PhD Student > University of Hamburg > Biozentrum Grindel und Zoologisches Museum > Abt. Säugetiere > Martin-Luther-King-Platz 3 > D-20146 Hamburg, GERMANY > +49(0)40 42838 6231 > ivan.calan...@uni-hamburg.de > > ********** > http://www.for771.uni-bonn.de > http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php > > > ______________________________________________ > 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]]
______________________________________________ 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.
