[R] How do I get the row indices?

[Achim Zeileis]

On Fri, 16 Sep 2005 10:34:57 -0700 (PDT) Martin Lam wrote:

> Hi,
> 
> I was wondering if it's possible to get the row
> numbers from a filtering. Here's an example:
> 
> # give me the rows with sepal.length == 6.2
> iris[(iris[,1]==6.2),]
> 
> # output
>     Sepal.Length Sepal.Width Petal.Length Petal.Width 
>   Species
> 69           6.2         2.2          4.5         1.5
> versicolor
> 98           6.2         2.9          4.3         1.3
> versicolor
> 127          6.2         2.8          4.8         1.8 
> virginica
> 149          6.2         3.4          5.4         2.3 
> virginica
> 
> What I really want is that it return the row numbers:
> 69, 98, 127, 149.

R> which(iris[,1]==6.2)
[1]  69  98 127 149

hth,
Z

> Thanks in advance,
> 
> Martin
> 
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