I have data in an excel csv file, on which I want to run PCA.

I'm not sure how the prcomp formula works. The help page states:

prcomp(x, retx = TRUE, center = TRUE, scale. = FALSE,

tol = NULL, ...)

what is x referring to? I tried putting the file name for x, but i get the following error:

Error in colMeans(x, na.rm = TRUE) : 'x' must be numeric

what kind of numeric value do I need to put in for x?

Potentially helpful information: my data sheet has around 48 columns and over 7000 rows. I have converted the csv file into a matrix in R.

Thanks in advance for all your help