# st: AW: RE: AW: How to form a vector for each line

 From "Martin Weiss" To Subject st: AW: RE: AW: How to form a vector for each line Date Thu, 15 Oct 2009 19:03:20 +0200

<>

That was a little subjective, admittedly, as I have never used a vector
outside -mata-. This fact need not stand in the way of Steven`s happiness,
though...

HTH
Martin

-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Nick Cox
Gesendet: Donnerstag, 15. Oktober 2009 18:58
An: statalist@hsphsun2.harvard.edu
Betreff: st: RE: AW: How to form a vector for each line

I agree with the advice to use Mata.

Some readers may find Martin's opening sentence a little puzzling,
however. In Stata, as compared with Mata, there is no difficulty in
setting up row or column vectors, which are just matrices with one row
or column. In this sense, Stata has had the idea of vector for several
versions now.

Nick
n.j.cox@durham.ac.uk

Martin Weiss

Vectors are not really a well-known concept in Stata, although naturally
you
can have them in -mata-. I have never missed them, though, as you can do
what you want to do without them most of the time. What is it you want
to
achieve?

***
clear*

input byte( a b c)
3 4 3
2 3 4
2 5 6
2 0 4
end

compress
list, noobs

capt which tomata
if _rc ssc inst tomata

tomata a b c

mata
A=a,b,c
A[2,.]*A[2,.]'
A[2,.]'*A[2,.]
end

Steven Ho

Suppose I have a data like this:
a b c
3 4 3
2 3 4
2 5 6
2 0 4

What I want is something like this, of course the following command
doesn't
work
gen arrayZ[_n]=( a[_n], b[_n], c[_n])
so that arrayZ[3] for example would be (2,5,6)
ie. when I invoke Z[t] it will give me a VECTOR of t-th row

I need this because I will do a whole bunch of operations to Z[t]Z[t]'
How to achieve this?

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