st: novice Mata question

a postscript to my last posting: the Mata select() function is not in the Darth Vader manual. It is one of the number of Mata features that have been added to the language since Stata 9.0. When working with Mata, it is always useful to see what's not documented in hardcopy ; quite a long list appears in

help forthcoming

Kit Baum, Boston College Economics
http://ideas.repec.org/e/pba1.html
An Introduction to Modern Econometrics Using Stata:
http://www.stata-press.com/books/imeus.html

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