R help - Feb 2009 - How to sort a matrix or dataframe by two columns?

Dear all,

I have a matrix data and would like to sort it by col 1 first and then sort it
by col 2. Can I do it in R? Thanks a lot!

Bill

Yes, you can:

m <- matrix( sample(1:5, 20, rep=TRUE), nc=2)
m[ order(m[,1],m[,2]), ]

Gabor

On Fri, Feb 6, 2009 at 11:29 PM, Bill Hyman <billhyman1 at yahoo.com>
wrote:
> Dear all,
>
> I have a matrix data and would like to sort it by col 1 first and then sort
it by col 2. Can I do it in R? Thanks a lot!
>
> Bill
>
> ______________________________________________
> R-help at 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.
>


-- 
Gabor Csardi <Gabor.Csardi at unil.ch>     UNIL DGM

Gabor,

Thank you very much!

Bill



----- Original Message ----
From: G?bor Cs?rdi <csardi at rmki.kfki.hu>
To: Bill Hyman <billhyman1 at yahoo.com>
Cc: r-help at r-project.org
Sent: Friday, February 6, 2009 2:37:30 PM
Subject: Re: [R] How to sort a matrix or dataframe by two columns?

Yes, you can:

m <- matrix( sample(1:5, 20, rep=TRUE), nc=2)
m[ order(m[,1],m[,2]), ]

Gabor

On Fri, Feb 6, 2009 at 11:29 PM, Bill Hyman <billhyman1 at yahoo.com>
wrote:
> Dear all,
>
> I have a matrix data and would like to sort it by col 1 first and then sort
it by col 2. Can I do it in R? Thanks a lot!
>
> Bill
>
> ______________________________________________
> R-help at 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.
>


-- 
Gabor Csardi <Gabor.Csardi at unil.ch>     UNIL DGM