[R] matrix dimension and for loop
sonchawan tamkaew
psu17772 at yahoo.com
Tue Apr 9 14:46:40 CEST 2002
Dear all,
My questions are that if I have
> x<-rnorm(50)
> dim(x)<-c(10,5)
> y=1:5
> Z<-matrix(0,NROW(x),NROW(y))
> for (j in 1:NROW(y)) Z[,j]<-x[,j]*y[j]
1. Is there any other way to write this without 'for'
loop?
2. and if I don't know the dimension of x, which could
be only 1 column, how could I write the command
without using if (NCOL(x)==1), or something like that?
(in case I want to include them in my function.
Example of x is a vector.
> x<-rnorm(10)
> y=2
> Z<-matrix(0,NROW(x),NROW(y))
> for (j in 1:NROW(y)) Z[,j]<-x[,j]*y[j]
Error in x[, j] : incorrect number of dimensions
Could anyone please help me to solve these problem?
Thank you very much for your kindness.
Sonchawan Tamkaew
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