Re: [R] Turn factors to numeric
Not an answer but I find that DF - data.frame(let = letters[1:3], num = 1:3, stringsAsFactors = FALSE) is very handy. Damn it, if I want a factor I'll tell the machine I do :) Or you can also set this option globally with options(stringsAsFactors = TRUE) Gabor Grothendieck warns that this last can possibly cause problems when using R programs from other places. I ran into this problem once with reshape. --- On Thu, 10/9/08, Michael Kubovy [EMAIL PROTECTED] wrote: From: Michael Kubovy [EMAIL PROTECTED] Subject: Re: [R] Turn factors to numeric To: Charilaos Skiadas [EMAIL PROTECTED] Cc: r-help r-help@r-project.org Received: Thursday, October 9, 2008, 8:25 AM Dear R-helpers, The FAQ in question says: It may happen that when reading numeric data into R (usually, when reading in a file), they come in as factors. If f is such a factor object, you can use as.numeric(as.character(f)) to get the numbers back. More efficient, but harder to remember, is as.numeric(levels(f))[as.integer(f)] I wonder why the R Core group did not choose to make such a useful operation simpler for the user (i.e., something like a factor2numeric() function that would be a wrapper to the more efficient command). _ Professor Michael Kubovy University of Virginia Department of Psychology USPS: P.O.Box 400400Charlottesville, VA 22904-4400 Parcels:Room 102Gilmer Hall McCormick RoadCharlottesville, VA 22903 Office:B011+1-434-982-4729 Lab:B019+1-434-982-4751 Fax:+1-434-982-4766 WWW:http://www.people.virginia.edu/~mk9y/ On Oct 9, 2008, at 7:16 AM, Charilaos Skiadas wrote: R-FAQ 7.10: http://cran.r-project.org/doc/FAQ/R-FAQ.html#How-do-I-convert-factors-to-numeric_003f On Oct 9, 2008, at 6:59 AM, joseph kambeitz wrote: I am having some problems while trying to fit simple data. I aggregated some data using: data1 - aggregate(data1$T2, list=(SOA=data1$SOA), mean) unfortunatly this coerces my variable SOA into a factor. Therefore when a afterwards try to fit a simple equation to my variable T2 using a formula on SOA i get a error because SOA is a factor and that * is not meaningful for factors... nls(T2 ~ a + b*SOA, start=list(a=1,b=1), data=data1, trace=TRUE) In fact SOA is a numeric variable (in my experiments it is the time that passed!) so i would like to re-coerce it into a numeric variable to do the fit or to find a method to do the fit even though SOA is a factor. Thanks a lot for your help! Best Jokel [[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. __ 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.
[R] Turn factors to numeric
I am having some problems while trying to fit simple data. I aggregated some data using: data1 - aggregate(data1$T2, list=(SOA=data1$SOA), mean) unfortunatly this coerces my variable SOA into a factor. Therefore when a afterwards try to fit a simple equation to my variable T2 using a formula on SOA i get a error because SOA is a factor and that * is not meaningful for factors... nls(T2 ~ a + b*SOA, start=list(a=1,b=1), data=data1, trace=TRUE) In fact SOA is a numeric variable (in my experiments it is the time that passed!) so i would like to re-coerce it into a numeric variable to do the fit or to find a method to do the fit even though SOA is a factor. Thanks a lot for your help! Best Jokel -- Ist Ihr Browser Vista-kompatibel? Jetzt die neuesten __ 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.
Re: [R] Turn factors to numeric
R-FAQ 7.10: http://cran.r-project.org/doc/FAQ/R-FAQ.html#How-do-I-convert-factors- to-numeric_003f On Oct 9, 2008, at 6:59 AM, joseph kambeitz wrote: I am having some problems while trying to fit simple data. I aggregated some data using: data1 - aggregate(data1$T2, list=(SOA=data1$SOA), mean) unfortunatly this coerces my variable SOA into a factor. Therefore when a afterwards try to fit a simple equation to my variable T2 using a formula on SOA i get a error because SOA is a factor and that * is not meaningful for factors... nls(T2 ~ a + b*SOA, start=list(a=1,b=1), data=data1, trace=TRUE) In fact SOA is a numeric variable (in my experiments it is the time that passed!) so i would like to re-coerce it into a numeric variable to do the fit or to find a method to do the fit even though SOA is a factor. Thanks a lot for your help! Best Jokel -- Ist Ihr Browser Vista-kompatibel? Jetzt die neuesten __ 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. Haris Skiadas Department of Mathematics and Computer Science Hanover College __ 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.
Re: [R] Turn factors to numeric
Dear R-helpers, The FAQ in question says: It may happen that when reading numeric data into R (usually, when reading in a file), they come in as factors. If f is such a factor object, you can use as.numeric(as.character(f)) to get the numbers back. More efficient, but harder to remember, is as.numeric(levels(f))[as.integer(f)] I wonder why the R Core group did not choose to make such a useful operation simpler for the user (i.e., something like a factor2numeric() function that would be a wrapper to the more efficient command). _ Professor Michael Kubovy University of Virginia Department of Psychology USPS: P.O.Box 400400Charlottesville, VA 22904-4400 Parcels:Room 102Gilmer Hall McCormick RoadCharlottesville, VA 22903 Office:B011+1-434-982-4729 Lab:B019+1-434-982-4751 Fax:+1-434-982-4766 WWW:http://www.people.virginia.edu/~mk9y/ On Oct 9, 2008, at 7:16 AM, Charilaos Skiadas wrote: R-FAQ 7.10: http://cran.r-project.org/doc/FAQ/R-FAQ.html#How-do-I-convert-factors-to-numeric_003f On Oct 9, 2008, at 6:59 AM, joseph kambeitz wrote: I am having some problems while trying to fit simple data. I aggregated some data using: data1 - aggregate(data1$T2, list=(SOA=data1$SOA), mean) unfortunatly this coerces my variable SOA into a factor. Therefore when a afterwards try to fit a simple equation to my variable T2 using a formula on SOA i get a error because SOA is a factor and that * is not meaningful for factors... nls(T2 ~ a + b*SOA, start=list(a=1,b=1), data=data1, trace=TRUE) In fact SOA is a numeric variable (in my experiments it is the time that passed!) so i would like to re-coerce it into a numeric variable to do the fit or to find a method to do the fit even though SOA is a factor. Thanks a lot for your help! Best Jokel [[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.
