how to use attr?
Dear Jeff, The tsls function in the SEM package does 2SLS estimation using a formula interface for both the structural equation and the instruments. It only estimates one equation at a time, but perhaps you can use it as a model. I hope that this helps, John
At 11:54 AM 1/8/2002 -0800, Jeff D. Hamann wrote:
I'm trying to build a flexible OLS/SUR/2SLS/3SLS package and I'm having trouble getting some information out of a formula. For example.... # set up the system of equations demand <- q ~ p + d supply <- q ~ p + f + a inst <- ~ d + f + a systemeq <- list( demand, supply ) ...blah, blah, blah... # get the number if instruments... # or build the "bigX"... #I need to get a print of the variables to build a large matrix... print( attr( systemeq[[1]], "variables" ) ) I've tried all kinds of variants... names( systemeq[[1]] ) names( systemeq[[1]]$formula )
----------------------------------------------------- John Fox Department of Sociology McMaster University Hamilton, Ontario, Canada L8S 4M4 email: jfox at mcmaster.ca phone: 905-525-9140x23604 web: www.socsci.mcmaster.ca/jfox ----------------------------------------------------- -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._