[R] Conditional operation on columns in data frame

2006-03-11 Thread Sander Oom 
Dear R-users,

I need to do an SQL like, conditional, operation on a data frame using
an ifelse construction. However I can not get it to work.

Example:
 x1 - rnorm(10)
 x2 - rnorm(10)
 x3 - rnorm(10)
 x3 - NA
 y - cbind(x1,x2,x3)
 y
   x1  x2 x3
 [1,] -0.56927780 -0.30952274 NA
 [2,]  0.16355087  0.05911772 NA
 [3,] -0.21899354  2.04583752 NA
 [4,]  0.06368076  1.11661608 NA
 [5,] -1.30249878 -0.63354373 NA
 [6,]  0.04842365  1.47591928 NA
 [7,] -0.32364275 -0.62201121 NA
 [8,] -0.70427823 -0.15485223 NA
 [9,] -0.39563916  2.23504977 NA
[10,] -1.24102239 -0.40991140 NA

Now I want to fill a new column with values from either x2 or x3,
depending on the value in x1. I thought of something like this:
y$x4 - ifelse(y$x10,x2,x3)
y$x4 - apply(y,1, function(x) {ifelse(x$x10,x$x2,x$x3) })

But obviously this did not give the right result.

Any suggestions?

Thanks in advance,

Sander.

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Re: [R] Conditional operation on columns in data frame

2006-03-11 Thread Sander Oom 
Hi Hong Ooi,

Thanks for your reply! I tried this option as well, but the result is
not as I expect:

 y$x4 - ifelse(y$x10,y$x2,y$x3)
 y
$x4
logical(0)
 class(y)
[1] list

Any more ideas?

Thanks,

Sander.


Hong Ooi wrote:
 ___
 
 Note: This e-mail is subject to the disclaimer contained at the bottom of 
 this message.
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 x2 and x3 are not separate objects, but columns of y. So you need to specify 
 that.
  
 y$x4 - ifelse(y$x1  0, y$x2, y$x3)
  
  
 
 
 
 From: [EMAIL PROTECTED] on behalf of Sander Oom
 Sent: Sat 11/03/2006 11:23 PM
 To: r-help@stat.math.ethz.ch
 Subject: [R] Conditional operation on columns in data frame
 
 
 
 Dear R-users,
 
 I need to do an SQL like, conditional, operation on a data frame using
 an ifelse construction. However I can not get it to work.
 
 Example:
 x1 - rnorm(10)
 x2 - rnorm(10)
 x3 - rnorm(10)
 x3 - NA
 y - cbind(x1,x2,x3)
 y
x1  x2 x3
  [1,] -0.56927780 -0.30952274 NA
  [2,]  0.16355087  0.05911772 NA
  [3,] -0.21899354  2.04583752 NA
  [4,]  0.06368076  1.11661608 NA
  [5,] -1.30249878 -0.63354373 NA
  [6,]  0.04842365  1.47591928 NA
  [7,] -0.32364275 -0.62201121 NA
  [8,] -0.70427823 -0.15485223 NA
  [9,] -0.39563916  2.23504977 NA
 [10,] -1.24102239 -0.40991140 NA
 
 Now I want to fill a new column with values from either x2 or x3,
 depending on the value in x1. I thought of something like this:
 y$x4 - ifelse(y$x10,x2,x3)
 y$x4 - apply(y,1, function(x) {ifelse(x$x10,x$x2,x$x3) })
 
 But obviously this did not give the right result.
 
 Any suggestions?
 
 Thanks in advance,
 
 Sander.
 
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 https://stat.ethz.ch/mailman/listinfo/r-help
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Re: [R] Conditional operation on columns in data frame

2006-03-11 Thread Gabor Grothendieck 
y is of class matrix and $ is used for data frames, not matrices.
Use y[,x1] or else create a data frame, data.frame(x1, x2, x3).

On 3/11/06, Sander Oom [EMAIL PROTECTED] wrote:
 Dear R-users,

 I need to do an SQL like, conditional, operation on a data frame using
 an ifelse construction. However I can not get it to work.

 Example:
  x1 - rnorm(10)
  x2 - rnorm(10)
  x3 - rnorm(10)
  x3 - NA
  y - cbind(x1,x2,x3)
  y
   x1  x2 x3
  [1,] -0.56927780 -0.30952274 NA
  [2,]  0.16355087  0.05911772 NA
  [3,] -0.21899354  2.04583752 NA
  [4,]  0.06368076  1.11661608 NA
  [5,] -1.30249878 -0.63354373 NA
  [6,]  0.04842365  1.47591928 NA
  [7,] -0.32364275 -0.62201121 NA
  [8,] -0.70427823 -0.15485223 NA
  [9,] -0.39563916  2.23504977 NA
 [10,] -1.24102239 -0.40991140 NA

 Now I want to fill a new column with values from either x2 or x3,
 depending on the value in x1. I thought of something like this:
 y$x4 - ifelse(y$x10,x2,x3)
 y$x4 - apply(y,1, function(x) {ifelse(x$x10,x$x2,x$x3) })

 But obviously this did not give the right result.

 Any suggestions?

 Thanks in advance,

 Sander.

 __
 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


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