R help - Feb 2009 - non-numeric argument to binary operator

Hi,

I compute the value of xi*xj by "for" loops, this how I try:
> x1 <- c(1:3)
> x2 <- c(2:4)
### to compute x1*x2
> (paste("x", 1, sep = ""))*(paste("x", 2, sep
= ""))
Error in (paste("x", 1, sep = "")) * (paste("x",
2, sep = "")) :
  non-numeric argument to binary operator
>
All comments are appreciated.

Thanks,
cruz

hi: it's not clear to me what you're trying to do but maybe outer is 
what you want ?

outer(x,y)

it takes every value in x and  pairs it with every value in y and the 
default operation is multiply. see details by doing ?outer.



On Wed, Feb 4, 2009 at 10:36 PM, cruz wrote:
> Hi,
>
> I compute the value of xi*xj by "for" loops, this how I try:
>
>> x1 <- c(1:3)
>> x2 <- c(2:4)
>
> ### to compute x1*x2
>
>> (paste("x", 1, sep = ""))*(paste("x", 2,
sep = ""))
> Error in (paste("x", 1, sep = "")) *
(paste("x", 2, sep = "")) :
>   non-numeric argument to binary operator
>>
>
> All comments are appreciated.
>
> Thanks,
> cruz
>
> ______________________________________________
> 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.

You are making difficulties where there are none.  Consider
> x1 <- 1:3     #  Why c(...)?
> x2 <- 2:4
> x12 <- x1*x2  #  element by element product  (matlab .* operator)
> x12
[1]  2  6 12
> x12 <- outer(x1, x2)  # another possibility - outer product
> x12
     [,1] [,2] [,3]
[1,]    2    3    4
[2,]    4    6    8
[3,]    6    9   12
> x12 <- x1 %*% x2      # yet another possibility - inner product
> x12
     [,1]
[1,]   20
>  
It's probably best if you start learning R by reading the introductory
material and trying it out. If the going gets tough, persevere. Trying to learn
R directly from R-help can get a bit tedious (on both sides).

Bill Venables
http://www.cmis.csiro.au/bill.venables/ 


-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of cruz
Sent: Thursday, 5 February 2009 1:36 PM
To: r-help at r-project.org
Subject: [R] non-numeric argument to binary operator

Hi,

I compute the value of xi*xj by "for" loops, this how I try:
> x1 <- c(1:3)
> x2 <- c(2:4)
### to compute x1*x2
> (paste("x", 1, sep = ""))*(paste("x", 2, sep
= ""))
Error in (paste("x", 1, sep = "")) * (paste("x",
2, sep = "")) :
  non-numeric argument to binary operator
>
All comments are appreciated.

Thanks,
cruz

______________________________________________
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.