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Column Indexes
Syntax
col(x, as.factor=FALSE)
Arguments
x
a matrix.
as.factor
a logical value indicating whether the value should be returned as a factor rather than as numeric.
Value
An integer matrix with the same dimensions as
x
and whose
ij
-th element is equal to
j
.
See Also
row
to get rows.
Examples
# extract the diagonal of a matrix dx <- x[row(x)==col(x)] # create an identity 5-by-5 matrix x <- matrix(0,nr=5,nc=5) x[row(x)==col(x)] <- 1