# Attributes Example
# Show examples of how to access and 
# change the attributes of R objects.

M <- matrix(c(4.5, 2.9, 0.7, 4.0), 2, 2, byrow=T)
cat('Matrix M:\n')
print(M)
cat('Attributes of M:\n')
print(attributes(M))

# Now create a matrix with dimnames attributes.
A <- matrix(c(34, 8, -2, 21), 2, 2, byrow=T,
   dimnames=list(c('r1', 'r2'), c('c1', 'c2')))
print(A)
print(attributes(A))

# See what these matrices look like if you consider
# them to be vectors.
print(as.vector(M))
print(as.vector(A))

# M and A are not vectors because of their extra attributes.
print(is.vector(M))
print(is.vector(A))

# We can change M and A into vectors by throwing 
# away their attributes.
dim(M) <- NULL
dim(A) <- NULL
dimnames(A) <- NULL
cat('Are M and A vectors?\n')
cat(is.vector(M), '  ', is.vector(A), '\n')
cat('Matrix M:\n')
print(M)
cat('Matrix A:\n')
print(A)