df<-data.frame()
df[1:8,1]<-c("1","2","5","3","1","4","3","5") ##identifier 1
df[1:8,2]<-c("c","a","b","c","a","b","b","a") ##identifier 2
df[1:8,3]<-c(1,2,3,4,5,6,7,8) ##value##Each unique combination of identifiers identifies a datapoint ##What I am trying to do is create a matrix with values of the third column ## and rows/column names of the 1st and 2nd column. As you can see, a lot of ## combinations of identifier1 and identifier 2, for example (1,b), do not ## have a value attached to them, and I would like those values in the matrix ## to be NA. ##From the ecodist, I have tried crosstab(df[,1],df[,2],df[,3]) ##It works perfectly in this case, but when I use it on my actual data.frame ##It ALWAYS crashes..differences between my real data.frame ## 1)Actual df is 3 million rows, 2)df[,1] and df[,2] are ## of class "factor" rather than class "character" ## knowing this I have tried as.character(df[,1]) & same for df2 ##but to no avail -- View this message in context: http://r.789695.n4.nabble.com/Converting-3-columns-of-a-data-frame-into-a-matrix-tp2263540p2263540.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ [email protected] 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.
