PCA in R

From Augix' Wiki

In R, one can perform a Principle component analysis with function named "prcomp" or "princomp".

    ## The variances of the variables in the
    ## USArrests data vary by orders of magnitude, so scaling is appropriate
    (pc.cr <- princomp(USArrests))  # inappropriate
    princomp(USArrests, cor = TRUE) # =^= prcomp(USArrests, scale=TRUE)
    ## Similar, but different:
    ## The standard deviations differ by a factor of sqrt(49/50)