R help - Jun 2010 - adding column of ordered numbers to matrix

Hello everyone,

I have a matrix of over 40000 line and about 30 columns.

For my analysis I would like to add another column with ascending numbers
(column header should be "order", and than 1,2,3,4 ....the end of the
matrix).
During my analysis I reorder them ( due to merge commands by a different
column).

How do I add such a column in an ascending order (or descending for what it
matters)?

THX

Assa

	[[alternative HTML version deleted]]

Hi

r-help-bounces at r-project.org napsal dne 10.06.2010 15:56:06:
> Hello everyone,
> 
> I have a matrix of over 40000 line and about 30 columns.
Matrix or data.frame?
> 
> For my analysis I would like to add another column with ascending 
numbers
> (column header should be "order", and than 1,2,3,4 ....the end of
the
> matrix).
If data frame DF

DF$order <- 1:nrow(DF)

in case of matrix mat
mat <- cbind(mat, "order"=1:nrow(mat))

Regards
Petr

PS. order is built in function so it is not especially wise to use it as a 
name for some object/column

> During my analysis I reorder them ( due to merge commands by a different
> column).
> 
> How do I add such a column in an ascending order (or descending for what 
it
> matters)?
> 
> THX
> 
> Assa
> 
>    [[alternative HTML version deleted]]
> 
> ______________________________________________
> 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.

> newmat <- cbind( oldmat, order=seq(nrow(oldmat)) )
See ?seq and/or ?rev for descending.

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Assa Yeroslaviz
> Sent: Thursday, June 10, 2010 7:56 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] adding column of ordered numbers to matrix
> 
> Hello everyone,
> 
> I have a matrix of over 40000 line and about 30 columns.
> 
> For my analysis I would like to add another column with ascending
> numbers
> (column header should be "order", and than 1,2,3,4 ....the end of
the
> matrix).
> During my analysis I reorder them ( due to merge commands by a
> different
> column).
> 
> How do I add such a column in an ascending order (or descending for
> what it
> matters)?
> 
> THX
> 
> Assa
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> 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.