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eliza botto

2013-Apr-15 12:27 UTC

[R] Indices of lowest values in matrix

Dear R users,Sorry for such a basic question. I really need to know that how can
i pick the indices of 5 lowest values from each row of a matrix with dimensions
12*12??Thank you very much in advance
Elisa
 		 	   		  
	[[alternative HTML version deleted]]

peter dalgaard

2013-Apr-15 12:50 UTC

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[R] Indices of lowest values in matrix

On Apr 15, 2013, at 14:27 , eliza botto wrote:
> Dear R users,Sorry for such a basic question. I really need to know that
how can i pick the indices of 5 lowest values from each row of a matrix with
dimensions 12*12??Thank you very much in advance
Something like this?
> m      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
 [1,]  1.2 -2.5  0.4 -0.2  1.4 -1.8 -1.6 -0.1 -0.1  -0.3  -0.2  -0.5
 [2,] -0.2 -1.9  0.9  0.0 -1.0  0.2 -0.8  0.7 -1.5  -1.4   1.8   0.4
 [3,] -0.9  0.7  0.4 -0.4 -1.6  0.6  1.1 -0.9  2.3   1.0   0.6   0.8
 [4,]  1.4 -0.7  0.0 -2.3  0.4  1.0  1.5 -0.8  1.0  -0.1   0.6   0.3
 [5,]  0.8 -0.1  1.3 -0.1  1.8 -0.7 -1.4 -0.9  0.6   0.7   0.3   1.4
 [6,]  0.4  0.0  0.6 -0.4  0.7 -0.3  1.5  1.6 -1.9  -1.1   0.3   0.6
 [7,]  0.5 -0.4 -1.9 -2.4  0.3  0.3  0.1  0.6 -0.9   0.2   0.0   1.4
 [8,] -0.2  0.4 -1.4 -0.1 -0.1  1.2  0.2  0.0 -0.9   0.4  -0.3  -2.0
 [9,] -0.3  1.0 -0.7  0.9 -1.7 -0.8  1.8 -0.4  0.1   0.2   0.4   1.2
[10,] -0.6  0.7 -0.1  0.3  1.4  0.7 -0.1  1.0 -0.8   0.9   0.0  -0.6
[11,] -0.1  0.2  0.4 -0.3 -1.5 -0.2  1.0  1.0 -0.5  -0.4  -1.2   1.1
[12,] -1.1  0.3  0.7 -0.9  0.2 -1.0  0.2 -1.1 -1.2  -0.3   0.8  -0.9
> apply(m,1,order)[1:5,]     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
[1,]    2    2    5    4    7    9    4   12    5     9     5     9
[2,]    6    9    1    8    8   10    3    3    6     1    11     1
[3,]    7   10    8    2    6    4    9    9    3    12     9     8
[4,]   12    5    4   10    2    6    2   11    8     3    10     6
[5,]   10    7    3    3    4    2   11    1    1     7     4     4


-- 
Peter Dalgaard, Professor
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com

arun

2013-Apr-15 13:53 UTC

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[R] Indices of lowest values in matrix

Hi,
TRy this:
set.seed(30)
?mat1<- matrix(sample(1:50,12*12,replace=TRUE),ncol=12)
mat1
????? [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
?[1,]??? 5?? 28?? 13??? 4?? 47??? 3?? 30?? 16??? 3??? 39??? 42???? 9
?[2,]?? 25?? 44?? 15?? 21??? 9??? 5?? 32??? 5??? 4??? 33??? 30??? 21
?[3,]?? 19?? 12?? 24??? 2??? 7?? 37?? 36??? 3?? 13???? 9??? 33??? 33
?[4,]?? 22?? 47?? 13?? 14??? 9?? 29?? 20??? 3??? 1??? 25??? 14??? 29
?[5,]?? 16?? 13?? 41?? 22?? 15?? 39?? 50?? 44?? 10??? 50??? 32??? 32
?[6,]??? 8?? 42?? 24?? 32?? 21?? 31?? 45?? 32?? 41??? 44??? 22??? 31
?[7,]?? 45?? 31?? 31?? 39??? 4?? 25??? 1?? 19?? 28??? 16??? 20??? 48
?[8,]?? 12?? 22?? 12?? 25?? 45?? 10??? 5??? 7?? 31??? 27??? 18??? 30
?[9,]?? 49??? 8?? 25?? 10??? 6?? 30??? 8?? 29?? 14??? 10??? 48??? 44
[10,]??? 8?? 30?? 31?? 35??? 4?? 50?? 25?? 33??? 7??? 15??? 17??? 38
[11,]??? 4??? 2?? 15?? 40?? 30?? 49?? 44?? 14??? 3??? 33??? 41??? 12
[12,]?? 20?? 17?? 34?? 14?? 43??? 2?? 40?? 50?? 42??? 42??? 23??? 20


#If you need the lowest values:
?sapply(seq_len(nrow(mat1)),function(i) {x1<- mat1[i,]; x1[order(x1)][1:5]})
#??? [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
#[1,]??? 3??? 4??? 2??? 1?? 10??? 8??? 1??? 5??? 6???? 4???? 2???? 2
#[2,]??? 3??? 5??? 3??? 3?? 13?? 21??? 4??? 7??? 8???? 7???? 3??? 14
#[3,]??? 4??? 5??? 7??? 9?? 15?? 22?? 16?? 10??? 8???? 8???? 4??? 17
#[4,]??? 5??? 9??? 9?? 13?? 16?? 24?? 19?? 12?? 10??? 15??? 12??? 20
#[5,]??? 9?? 15?? 12?? 14?? 22?? 31?? 20?? 12?? 10??? 17??? 14??? 20


#indices

sapply(seq_len(nrow(mat1)),function(i) {order(mat1[i,])})[1:5,]
? # ? [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
#[1,]??? 6??? 9??? 4??? 9??? 9??? 1??? 7??? 7??? 5???? 5???? 2???? 6
#[2,]??? 9??? 6??? 8??? 8??? 2??? 5??? 5??? 8??? 2???? 9???? 9???? 4
#[3,]??? 4??? 8??? 5??? 5??? 5?? 11?? 10??? 6??? 7???? 1???? 1???? 2
#[4,]??? 1??? 5?? 10??? 3??? 1??? 3??? 8??? 1??? 4??? 10??? 12???? 1
#[5,]?? 12??? 3??? 2??? 4??? 4??? 6?? 11??? 3?? 10??? 11???? 8??? 12
A.K.





----- Original Message -----
From: eliza botto <eliza_botto at hotmail.com>
To: "r-help at r-project.org" <r-help at r-project.org>
Cc: 
Sent: Monday, April 15, 2013 8:27 AM
Subject: [R] Indices of lowest values in matrix

Dear R users,Sorry for such a basic question. I really need to know that how can
i pick the indices of 5 lowest values from each row of a matrix with dimensions
12*12??Thank you very much in advance
Elisa
??? ???  ??? ?  ??? ??? ? 
??? [[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.

eliza botto

2013-Apr-15 15:18 UTC

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[R] Indices of lowest values in matrix

Dear Arun,
Thankyou very much. it worked out
:D
Elisa
> Date: Mon, 15 Apr 2013 07:19:40 -0700
> From: smartpink111@yahoo.com
> Subject: Re: [R] Indices of lowest values in matrix
> To: eliza_botto@hotmail.com
> 
> Hi Elisa,
> I am not sure how you got that values for the first rows of mat1.  Is it
from other dataset
> set.seed(30)
>  mat1<- matrix(sample(1:50,12*12,replace=TRUE),ncol=12)
> mat1[1,]
> # [1]  5 28 13  4 47  3 30 16  3 39 42  9
> #So, here the lowest 5 values are 3,3,4,5,9
> 
> sort(mat1[1,],index.return=TRUE)
> #$x
>  #[1]  3  3  4  5  9 13 16 28 30 39 42 47
> 
> #$ix 
> 
> #[1]  6  9  4  1 12  3  8  2  7 10 11  5
> 
> From my previous solution:
> sapply(seq_len(nrow(mat1)),function(i) {order(mat1[i,])})[1:5,1]
> #[1]  6  9  4  1 12 #which are the column numbers.
> A.K.
> 
> 
> ________________________________
>  From: eliza botto <eliza_botto@hotmail.com>
> To: "smartpink111@yahoo.com" <smartpink111@yahoo.com> 
> Sent: Monday, April 15, 2013 10:09 AM
> Subject: RE: [R] Indices of lowest values in matrix
>  
> 
> 
>  
> Thankyou very much.
> 
> 
> one additional question is that what if i am interest to find that along
the row 1 which are 5 lowest values?  more precisely, for row 1 of mat1 the five
lowest values are
> 
> 3,5,8,19,21
> 
> therefore, i should have
> 
> 1,2,8,5,4 (the column numbers which contain these values)
> 
> Thanks in advance
> 
> Elisa
> 
> 
> 
> > Date: Mon, 15 Apr 2013 06:53:32 -0700
> > From: smartpink111@yahoo.com
> > Subject: Re: [R] Indices of lowest values in matrix
> > To: eliza_botto@hotmail.com
> > CC: r-help@r-project.org
> > 
> > Hi,
> > TRy this:
> > set.seed(30)
> > Ámat1<- matrix(sample(1:50,12*12,replace=TRUE),ncol=12)
> > mat1
> > ÁÁÁÁÁ [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
> > Á[1,]ÁÁÁ 5ÁÁ 28ÁÁ 13ÁÁÁ 4ÁÁ 47ÁÁÁ 3ÁÁ 30ÁÁ 16ÁÁÁ 3ÁÁÁ 39ÁÁÁ 42ÁÁÁÁ 9
> > Á[2,]ÁÁ 25ÁÁ 44ÁÁ 15ÁÁ 21ÁÁÁ 9ÁÁÁ 5ÁÁ 32ÁÁÁ 5ÁÁÁ 4ÁÁÁ 33ÁÁÁ 30ÁÁÁ 21
> > Á[3,]ÁÁ 19ÁÁ 12ÁÁ 24ÁÁÁ 2ÁÁÁ 7ÁÁ 37ÁÁ 36ÁÁÁ 3ÁÁ 13ÁÁÁÁ 9ÁÁÁ 33ÁÁÁ 33
> > Á[4,]ÁÁ 22ÁÁ 47ÁÁ 13ÁÁ 14ÁÁÁ 9ÁÁ 29ÁÁ 20ÁÁÁ 3ÁÁÁ 1ÁÁÁ 25ÁÁÁ 14ÁÁÁ 29
> > Á[5,]ÁÁ 16ÁÁ 13ÁÁ 41ÁÁ 22ÁÁ 15ÁÁ 39ÁÁ 50ÁÁ 44ÁÁ 10ÁÁÁ 50ÁÁÁ 32ÁÁÁ 32
> > Á[6,]ÁÁÁ 8ÁÁ 42ÁÁ 24ÁÁ 32ÁÁ 21ÁÁ 31ÁÁ 45ÁÁ 32ÁÁ 41ÁÁÁ 44ÁÁÁ 22ÁÁÁ 31
> > Á[7,]ÁÁ 45ÁÁ 31ÁÁ 31ÁÁ 39ÁÁÁ 4ÁÁ 25ÁÁÁ 1ÁÁ 19ÁÁ 28ÁÁÁ 16ÁÁÁ 20ÁÁÁ 48
> > Á[8,]ÁÁ 12ÁÁ 22ÁÁ 12ÁÁ 25ÁÁ 45ÁÁ 10ÁÁÁ 5ÁÁÁ 7ÁÁ 31ÁÁÁ 27ÁÁÁ 18ÁÁÁ 30
> > Á[9,]ÁÁ 49ÁÁÁ 8ÁÁ 25ÁÁ 10ÁÁÁ 6ÁÁ 30ÁÁÁ 8ÁÁ 29ÁÁ 14ÁÁÁ 10ÁÁÁ 48ÁÁÁ 44
> > [10,]ÁÁÁ 8ÁÁ 30ÁÁ 31ÁÁ 35ÁÁÁ 4ÁÁ 50ÁÁ 25ÁÁ 33ÁÁÁ 7ÁÁÁ 15ÁÁÁ 17ÁÁÁ 38
> > [11,]ÁÁÁ 4ÁÁÁ 2ÁÁ 15ÁÁ 40ÁÁ 30ÁÁ 49ÁÁ 44ÁÁ 14ÁÁÁ 3ÁÁÁ 33ÁÁÁ 41ÁÁÁ 12
> > [12,]ÁÁ 20ÁÁ 17ÁÁ 34ÁÁ 14ÁÁ 43ÁÁÁ 2ÁÁ 40ÁÁ 50ÁÁ 42ÁÁÁ 42ÁÁÁ 23ÁÁÁ 20
> > 
> > 
> > #If you need the lowest values:
> > Ásapply(seq_len(nrow(mat1)),function(i) {x1<- mat1[i,];
x1[order(x1)][1:5]})
> > #ÁÁÁ [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
> > #[1,]ÁÁÁ 3ÁÁÁ 4ÁÁÁ 2ÁÁÁ 1ÁÁ 10ÁÁÁ 8ÁÁÁ 1ÁÁÁ 5ÁÁÁ 6ÁÁÁÁ 4ÁÁÁÁ 2ÁÁÁÁ 2
> > #[2,]ÁÁÁ 3ÁÁÁ 5ÁÁÁ 3ÁÁÁ 3ÁÁ 13ÁÁ 21ÁÁÁ 4ÁÁÁ 7ÁÁÁ 8ÁÁÁÁ 7ÁÁÁÁ 3ÁÁÁ 14
> > #[3,]ÁÁÁ 4ÁÁÁ 5ÁÁÁ 7ÁÁÁ 9ÁÁ 15ÁÁ 22ÁÁ 16ÁÁ 10ÁÁÁ 8ÁÁÁÁ 8ÁÁÁÁ 4ÁÁÁ 17
> > #[4,]ÁÁÁ 5ÁÁÁ 9ÁÁÁ 9ÁÁ 13ÁÁ 16ÁÁ 24ÁÁ 19ÁÁ 12ÁÁ 10ÁÁÁ 15ÁÁÁ 12ÁÁÁ 20
> > #[5,]ÁÁÁ 9ÁÁ 15ÁÁ 12ÁÁ 14ÁÁ 22ÁÁ 31ÁÁ 20ÁÁ 12ÁÁ 10ÁÁÁ 17ÁÁÁ 14ÁÁÁ 20
> > 
> > 
> > #indices
> > 
> > sapply(seq_len(nrow(mat1)),function(i) {order(mat1[i,])})[1:5,]
> > Á # Á [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
> > #[1,]ÁÁÁ 6ÁÁÁ 9ÁÁÁ 4ÁÁÁ 9ÁÁÁ 9ÁÁÁ 1ÁÁÁ 7ÁÁÁ 7ÁÁÁ 5ÁÁÁÁ 5ÁÁÁÁ 2ÁÁÁÁ 6
> > #[2,]ÁÁÁ 9ÁÁÁ 6ÁÁÁ 8ÁÁÁ 8ÁÁÁ 2ÁÁÁ 5ÁÁÁ 5ÁÁÁ 8ÁÁÁ 2ÁÁÁÁ 9ÁÁÁÁ 9ÁÁÁÁ 4
> > #[3,]ÁÁÁ 4ÁÁÁ 8ÁÁÁ 5ÁÁÁ 5ÁÁÁ 5ÁÁ 11ÁÁ 10ÁÁÁ 6ÁÁÁ 7ÁÁÁÁ 1ÁÁÁÁ 1ÁÁÁÁ 2
> > #[4,]ÁÁÁ 1ÁÁÁ 5ÁÁ 10ÁÁÁ 3ÁÁÁ 1ÁÁÁ 3ÁÁÁ 8ÁÁÁ 1ÁÁÁ 4ÁÁÁ 10ÁÁÁ 12ÁÁÁÁ 1
> > #[5,]ÁÁ 12ÁÁÁ 3ÁÁÁ 2ÁÁÁ 4ÁÁÁ 4ÁÁÁ 6ÁÁ 11ÁÁÁ 3ÁÁ 10ÁÁÁ 11ÁÁÁÁ 8ÁÁÁ 12
> > A.K.
> > 
> > 
> > 
> > 
> > 
> > ----- Original Message -----
> > From: eliza botto <eliza_botto@hotmail.com>
> > To: "r-help@r-project.org" <r-help@r-project.org>
> > Cc: 
> > Sent: Monday, April 15, 2013 8:27 AM
> > Subject: [R] Indices of lowest values in matrix
> > 
> > Dear R users,Sorry for such a basic question. I really need to know
that how can i pick the indices of 5 lowest values from each row of a matrix
with dimensions 12*12??Thank you very much in advance
> > Elisa
> > ÁÁÁ ÁÁÁ  ÁÁÁ Á  ÁÁÁ ÁÁÁ Á 
> > ÁÁÁ [[alternative HTML version deleted]]
> > 
> > ______________________________________________
> > R-help@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.
> >  		 	   		  
	[[alternative HTML version deleted]]

R help - Apr 2013 - Indices of lowest values in matrix

[R] Indices of lowest values in matrix

[R] Indices of lowest values in matrix

[R] Indices of lowest values in matrix

[R] Indices of lowest values in matrix

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