How to sort a dataframe?

df1 <- data.frame(a=rep(2:1, 2), b=rep(2:1, each=2), c=1:4)

How does one sort a dataframe on multiple columns, say you first sort 
on variable 1 and then on variable 2, etc.? Is there a simple, one-
liner to do this?

thanks,
Ravi.

----- Original Message -----
From: Spencer Graves <spencer.graves at pdf.com>
Date: Monday, April 7, 2003 2:07 pm
Subject: Re: [R] How to sort a dataframe?

tester <- data.frame(one=c(3,2,1), two=c(2,3,1))
tester[order(tester$one),]

 one two
3   1   1
2   2   3
1   3   2

Spencer Graves

Remko Duursma wrote:

Dear R-helpers,

for the purpose of plotting a dataframe, i am trying to sort a 

dataframe by one column, for example

tester <- data.frame(one=c(3,2,1), two=c(2,3,1))

#> tester
#  one two
#1   3   2
#2   2   3
#3   1   1

# I want to sort "tester" by column "one", so that i get a dataframe
# that looks like:
#one two
#1    1
#2    3
#3    2

I know of 'sort' but it can only sort vectors.

Thanks for your help,

Remko Duursma