[R] Odp: adding column of ordered numbers to matrix

[Petr PIKAL]

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
> 
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> 
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