[R] factor analysis (pca): how to get the 'communalities'?

bmagill@earthlink.net bmagill at earthlink.net
Sat Jan 4 18:05:05 CET 2003

On 4 Jan 2003 at 12:51, Wolfgang Lindner wrote:

> Please excuse me, if the following questions are *too* off-topic, but I found it 
> interesting. In inspecting your code I came across an R feature, I could not 
> find in the online manuals:
> Q1. Looking at the left-handside in your function def:
> "cov.cor" <- function ( covmat ) {
>                         sdev <- diag ( sqrt ( diag ( covmat ) ) ) 
>                         solve(sdev) %*% covmat %*% t(solve(sdev))  }
> ^       ^
> |       |
> ?       ?
> - *Why* is the (identifier) function name cov.cor included in question marks? 
> - How is "cov.cor" then called?  "cov.cor"(..) or cov.cor(..) or ?

The quotation marks are the result of using dump() to write the set of functions to a 
file.  As was pointed out, it is not necessary to use quotation marks when calling any 
of these  functions.

As far as documentation, I simply have not done it yet.  In the meantime, if you have 
specific questions about how to use some of the functions, I can provide some 
examples and some on the fly documentation, let me know, specifically, what you 
want to use/know.  That, we should probably take off-list however.

In generall, you can source() the .R file in.  After doing that the entire set of functions 
will be available in your workspace for you to see using ls() and examine by calling 
the function name.

Regards, Brett

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