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help with simple function

4 messages · Miguel Eduardo Delgado Burbano, Berend Hasselman, arun +1 more

Original
Berend Hasselman
#
On 17-03-2013, at 16:47, Miguel Eduardo Delgado Burbano <mdelgadoburbano at gmail.com> wrote:

            

      
      
      
    

        
Write 4*( instead of 4( assuming you want to multiply.

            

      
      
      
    

        
[ is an indexing operator. You are trying to index the number 4. Which is impossible.

Berend

            

      
      
      
    

        

      
      
    

  
  


  


      

    

    

      
      

        


  

        

      arun
    

    

      
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Hi,

?Y1<- 1:4
?Y2<- 5:8

sqrt(var(Y1)+var(Y2)^2)-4*((var(Y1)*(var(Y2)-cov(Y1,Y2)^2)))
#[1] 9.515593
A.K.

----- Original Message -----
From: Miguel Eduardo Delgado Burbano <mdelgadoburbano at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Sunday, March 17, 2013 11:47 AM
Subject: [R] help with simple function

hello all

I am writing a quite simple script to study dental wear patterns in humans
and I wrote this function

sqrt(var(Y1)+var(Y2))^2-4(var(Y1)*(var(Y2)-cov(Y1,Y2)^2)) but appear this
error message

Error: attempt to apply non-function

alternatively I wrote this
sqrt(var(Y1)+var(Y2)^2)-4[(var(Y1)*(var(Y2)-cov(Y1,Y2)^2))]

but this error message appear

[1] NA
Warning message:
NAs introduced by coercion

some suggestion to solve this?? thank you so much for your help

Miguel

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      Rui Barradas
    

    

      
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Hello,

You are missing a '*' in your first try.
(As for the second, in R parenthesis are round, not [])

sqrt(var(Y1) + var(Y2))^2 - 4*(var(Y1)*(var(Y2) - cov(Y1, Y2)^2))

This written as a function becomes

fun <- function(Y1, Y2)
	sqrt(var(Y1) + var(Y2))^2 - 4*(var(Y1)*(var(Y2) - cov(Y1, Y2)^2))

x1 <- rnorm(10)
x2 <- rnorm(10)
fun(x1, x2)


Hope this helps,

Rui Barradas

Em 17-03-2013 15:47, Miguel Eduardo Delgado Burbano escreveu: