R help - Jan 2007 - how to get the index of entry with max value in an array?

Hi all:
         A short question:
         For example,  a=[3,4,6,2,3], obviously the 3rd entry of the array has
the maxium value, what I want is index of the maxium value: 3. is there a neat
expression to get this index?

Thank you!

Best,

Feng


	[[alternative HTML version deleted]]

?which.max
?which.is.min

On Wed, 17 Jan 2007, Feng Qiu wrote:
> Hi all:
>         A short question:
>         For example,  a=[3,4,6,2,3], obviously the 3rd entry of the array
has the maxium value, what I want is index of the maxium value: 3. is there a
neat expression to get this index?
>
> Thank you!
>
> Best,
>
> Feng
>
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
>
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

which.max
> a <- sample(1:10,10)
> a
 [1]  3  4  5  7  2  8  9  6 10  1
> which.max(a)
[1] 9
>


On 1/17/07, Feng Qiu <hellokisas@gmail.com> wrote:
>
> Hi all:
>         A short question:
>         For example,  a=[3,4,6,2,3], obviously the 3rd entry of the array
> has the maxium value, what I want is index of the maxium value: 3. is there
> a neat expression to get this index?
>
> Thank you!
>
> Best,
>
> Feng
>
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@stat.math.ethz.ch 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.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?

	[[alternative HTML version deleted]]

Or
which.max(a)

-Christos 

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of talepanda
Sent: Wednesday, January 17, 2007 11:45 PM
To: Feng Qiu
Cc: r-help at stat.math.ethz.ch
Subject: Re: [R] how to get the index of entry with max value in an array?

In R language, one solution is:

a<-c(3,4,6,2,3)
which(a==max(a))


On 1/18/07, Feng Qiu <hellokisas at gmail.com>
wrote:
> Hi all:
>          A short question:
>          For example,  a=[3,4,6,2,3], obviously the 3rd entry of the 
> array has the maxium value, what I want is index of the maxium value: 
> 3. is there a neat expression to get this index?
>
> Thank you!
>
> Best,
>
> Feng
>
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
>
______________________________________________
R-help at stat.math.ethz.ch 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.

which.max()
b

On Jan 17, 2007, at 11:20 PM, Feng Qiu wrote:
> Hi all:
>          A short question:
>          For example,  a=[3,4,6,2,3], obviously the 3rd entry of  
> the array has the maxium value, what I want is index of the maxium  
> value: 3. is there a neat expression to get this index?
>
> Thank you!
>
> Best,
>
> Feng

Thank you guys! I got it.

Best,

Feng

----- Original Message ----- 
From: "Benilton Carvalho" <bcarvalh at jhsph.edu>
To: "Feng Qiu" <hellokisas at gmail.com>
Cc: <r-help at stat.math.ethz.ch>
Sent: Thursday, January 18, 2007 12:20 AM
Subject: Re: [R] how to get the index of entry with max value in an array?

> which.max()
> b
> 
> On Jan 17, 2007, at 11:20 PM, Feng Qiu wrote:
> 
>> Hi all:
>>          A short question:
>>          For example,  a=[3,4,6,2,3], obviously the 3rd entry of  
>> the array has the maxium value, what I want is index of the maxium  
>> value: 3. is there a neat expression to get this index?
>>
>> Thank you!
>>
>> Best,
>>
>> Feng