In the function call in 'apply', you are passed the values in the rows:

> set.seed(30)
> z = matrix(rnorm(10), 5, 2)
> apply(z, 1, function(x) sum(z[x,1]*1, z[x,2]*3))
[1] -0.908321  0.000000  0.000000 -5.822442 -5.822442
> z
           [,1]       [,2]
[1,] -1.2885182 -1.5113079
[2,] -0.3476894  0.1105080
[3,] -0.5216288 -0.7607962
[4,]  1.2734732 -0.6698970
[5,]  1.8245206  0.2745197
> sum(z[1,1]*1,
+ z[1,2]*3)
[1] -5.822442
>  # correct use of apply
> apply(z, 1, function(x) x[1]*1 + x[2]*3)
[1] -5.82244202 -0.01616527 -2.80401753 -0.73621789  2.64807967
>


On Tue, Apr 28, 2009 at 9:02 PM, megh <megh700004@yahoo.com> wrote:

>
> Hi all, can you please clarify me what is the wrong with following codes :
>
> set.seed(30)
> z = matrix(rnorm(10), 5, 2)
> apply(z, 1, function(x) sum(z[x,1]*1, z[x,2]*3))
>
> However I can not get the desired result. For example, "sum(z[1,1]*1,
> z[1,2]*3)" gives -5.822442 which is actually correct. Am I missing
> something
> in apply() function?
>
> Regards,
>
>
> --
> View this message in context:
> http://www.nabble.com/Help-on-apply%28%29-function-tp23288839p23288839.html
> Sent from the R help mailing list archive at Nabble.com.
>
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>



-- 
Jim Holtman
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