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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
st: RE: Re: vectors in STATA |

Date |
Fri, 13 Dec 2002 11:13:45 -0000 |

Alejandro Riaņo > > I used to program in Gauss, that's why I still think > > about matrixes and vectors when I'm doing my own > > programs. My question is the following > > > > I want to store the correlation between 2 variables by > > each pair of countries and then store this number(that > > would be r(rho)) in a vector, so at the end I would > > have a column with the correlation for each in pair of > > countries as a position in this vector. > > > > Do you know how can i do this in STATA ??? Scott Merryman > There is probably a better way to do this, but here is one method > > levels countries, local(levels) > matrix A = 1 > foreach x of local levels { > qui corr var1 var2 if rep == `x' > scalar rho`x' = r(rho) > matrix a`x' = rho`x' > matrix A = A \ a`x' > > } > matdelrc A, r(1) > Comment on Scott's posting ========================== Scott shows how to build up a solution more or less from first principles, which is always worth seeing. To help understand his posting, note that -levels- is user-written and on SSC and that -matdelrc- is also user-written and is part of a package issued in STB-50. -matdelrc- could be avoided by using -nullmat()-. Here is a shorter version (assuming i.a. that he was mixing examples): levels countries, local(levels) foreach x of local levels { qui corr var1 var2 if countries == `x' matrix A = nullmat(A) \ r(rho) } and you will probably want to follow with something like matrix rownames A = `levels' Alternative approach ===================== Check out -vectorof- and -matrixof-. They are both in the -matrixof- package on SSC. Example: . vectorof corr headroom-gear, y(mpg) r(rho) matname(corr) produces a vector of correlations between a set of variables and -mpg-. But you may still need to program your own, depending on your data structure. At worst, this would be two nested -foreach- loops. Nick n.j.cox@durham.ac.uk * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**st: Re: vectors in STATA***From:*"Scott Merryman" <smerryman@kc.rr.com>

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