Using your posed data, the variable price was numeric: data.precios <- read.table("http://r.789695.n4.nabble.com/file/n4498828/p_diarios.txt", header=T)
str(data.precios) 'data.frame': 1996 obs. of 2 variables: $ time : int 37988 37991 37993 37994 37995 37998 37999 38000 38001 38002 ... $ price: num 18.1 26.1 30.9 34.7 27.6 ... HOWEVER! If I follow your code (eg. using " read.table(... , dec=",", sep="\t")": data.precios <- read.table("http://r.789695.n4.nabble.com/file/n4498828/p_diarios.txt", header =TRUE , dec=",", sep="\t") > str(data.precios) 'data.frame': 1996 obs. of 2 variables: $ time : int 37988 37991 37993 37994 37995 37998 37999 38000 38001 38002 ... $ price: Factor w/ 1639 levels "10.80","12.53",..: 12 126 213 342 160 186 219 37 54 69 ... It is a factor.... but I can change it like this: > Price <- as.numeric(data.precios$price) > str(lPrice) num [1:1996] 12 126 213 342 160 186 219 37 54 69 ... I think avoiding it ever becoming a factor would be the better path. Good luck. sandro wrote > > Hello, I am relatively new to using R. > > The text file contains the date and price . I want to read and manipulate > the data in R. However, when I use read.table, it treats all of the data > as "factors" and I do not know how to treat the data as numbers: > > http://r.789695.n4.nabble.com/file/n4498828/p_diarios.txt p_diarios.txt > > setwd ("C:\\Users\\Sandro\\Dropbox\\R") > data.precios <- read.table ("p_diarios.txt ", header =TRUE > , dec=",", sep="\t") > Time <- data.precios$time # 01.02.2004 - 12.05.2011 > Price <- data.precios$price # Historical spot price > log.Price <- log(data.precios$price) > Error en Math.factor(c(12L, 126L, 213L, 342L, 160L, 186L, 219L, 37L, 54L, > : > log not meaningful for factors > > As you can see, I cannot calculate the price logarithms. > > Any help is appreciated. > > Sandro > -- View this message in context: http://r.789695.n4.nabble.com/How-to-convert-factors-to-numbers-tp4498828p4499019.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.