RE: [R] "chronological" ordering of factor in lm() and plot()

From: <>
Date: Sat 16 Apr 2005 - 15:42:46 EST

First put

> day.names <- c("sun", "mon", "tue", "wed", "thu", "fri", "sat")


> days <- factor(as.character(days), levels = day.names)

will ensure the ordering you want.

Bill Venables.

-----Original Message-----
[] On Behalf Of Eric C. Jennings Sent: Saturday, 16 April 2005 2:29 PM
To: R-help
Subject: [R] "chronological" ordering of factor in lm() and plot()

I am trying to do some basic regression and ANOVA on cycle times (numeric
vectors) across weekdays (character vector), where I have simply labelled my
days as:
days<- c("mon","tue","wed"...etc).
(NOTE: There are actually multiple instances of each day, and the data is
read-in from a .dat file.)

I have no trouble at all with the actual number crunching, It is the "proper" ordering of the factor that I am asking about. R first alphabetizes
it("fri","mon","thu"...) before doing the work of lm(), aov() and especially

I have tried as.ordered(factor( )), but that doesn't do anything. If I re-assign levels() in the way that I want, that just renames the the
levels of the factor but does not reorder it internally. I've looked at chron(), but that seems to entail using a numeric vector instead of a character vector.

How can I get it to "properly" (chronologically) order the factor. (In some
ways I'm thinking that all I can do is:
days<- c("a.mon","b.tues",""...etc)

Thanks for all that you can do
Eric Jennings mailing list PLEASE do read the posting guide! mailing list PLEASE do read the posting guide! Received on Sat Apr 16 15:51:38 2005

This archive was generated by hypermail 2.1.8 : Fri 03 Mar 2006 - 03:31:12 EST