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From | Nick Cox <n.j.cox@durham.ac.uk> |
To | "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu> |
Subject | st: RE: Re: Extracting a submatrix based on multiple conditions |
Date | Fri, 1 Jul 2011 12:29:19 +0100 |
: select(y, (y[,2] :== 1 :& y[,3] :== 1)) 1 2 3 4 5 +-----------------------------------------+ 1 | 18049 1 1 91 2500 | 2 | 18079 1 1 124 2300 | +-----------------------------------------+ Nick n.j.cox@durham.ac.uk Partho Sarkar I am very new to Mata, so please excuse if this is too naive. I have a very short question: In Mata, is there a way, and if so what, to extract a submatrix of rows where more than one condition is met, i.e., conditions on values in 2 or more columns? E.g., in the following matrix 1 2 3 4 5 +-----------------------------------------+ 1 | 18049 1 1 91 2500 | 2 | 18079 2 1 91 2500 | 3 | 18079 1 1 124 2300 | +-----------------------------------------+ I want to extract the rows where the column 2 value==1 AND column 3 value==1 . As far as I can see so far, this is possible for a single condition, e.g., y[.,3]:==1 would give me the row numbers where this condition is met. But this does not work ( I tried with various parentheses): y[.,3]:==1 & y[.1]:==1 * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/