[R] How to convert factors to numbers

[David Winsemius]

On Mar 23, 2012, at 9:38 AM, 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")

Why are you using dec="," when you have decimal points in the file?


> 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.

You could read the FAQ on this matter ... number 7.21 or in that  
general vicinity. But it would be easier to fix the error in your  
input statement.

-- 

David Winsemius, MD
West Hartford, CT