R help - May 2012 - Help "deleting negative values in a matrix, and do statistic analysis"

Hello,

Try
(x is your matrix)

rowMeans(x)
apply(x, 1, function(y) mean( y[y >= 0] ))


Hope this helps,

Rui Barradas

york8866 wrote
> 
> Dear all,
> 
> I have encountered a problem with such a dataset:
> 
> 1	52	2	5	2	6
> 15	23	2	1	3	3
> 2	5	1	9	8	9
> 6	-5	3	6	-5	96
> -1	6	3	8	5	9
> .	.	.	.	.	.
> .	.	.	.	.	.
> 
> 
> I want to calculate the means of each row of the dataset. In addition, I
> need to delete the negative values in each row first before the
> calculation of the means.
> 
> can anyone show me how to deal with it?
> 
> thanks,
> 

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Hi,  Rui,

I tried your code. It did not work. 

thanks,




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It looks fine to me. Why do you say it does not work?

Any error messages?

John Kane
Kingston ON Canada

> -----Original Message-----
> From: yu_york at hotmail.com
> Sent: Tue, 8 May 2012 10:06:07 -0700 (PDT)
> To: r-help at r-project.org
> Subject: Re: [R] Help "deleting negative values in a matrix, and do
> statistic analysis"
> 
> Hi,  Rui,
> 
> I tried your code. It did not work.
> 
> thanks,
> 
> 
> 
> 
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> View this message in context:
>
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> Sent from the R help mailing list archive at Nabble.com.
> 
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Hi, John,

the code ran well.

however, somehow, the means were not calculated correctly using the
following code.

test <- read.csv("Rtestdataset.csv", as.is=T,header=T)  
test <- data.frame(test)
test
rowMeans(test)
apply(test,1,function(y)mean(y>=0))

Is there anything wrong?
thanks,



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