[R] How do I get the row indices?

[Berton Gunter]

?row
row(iris)[iris[,1]==6.2]

##or better yet

?which
which(iris[,1]==6.2)

Note also that both may fail because the test may not be numerically exact
-- you may need to add fuzz.

-- Bert Gunter
Genentech Non-Clinical Statistics
South San Francisco, CA
 
"The business of the statistician is to catalyze the scientific learning
process."  - George E. P. Box
 
 

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Martin Lam
> Sent: Friday, September 16, 2005 10:35 AM
> To: R
> Subject: [R] How do I get the row indices?
> 
> 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.
> 
> Thanks in advance,
> 
> Martin
> 
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