st: collapse - mata question

[Enzo Coviello <enzo.coviello@alice.it>]

Dear Stata Users,

Assume that we have a matrix

1  1 0   28
1  1 1   27
2  0  0   26
2  1  1   25

In a corresponding Stata data set the first 
column is the variable -id-, the second is the 
variable -occ-, the third -ocx- and the fourth -day-

I want to obtain a matrix like that:

1  2  1   28
2  1   1  26

In the standard Stata language this is easy:
. collapse (sum) occ ocx (max) day, by(id)

I wonder how the same result can be obtained in mata?

Best wishes

Enzo



Enzo Coviello
Unit� di Epidemiologia e Statistica ASL BARI
Piazza V.  Emanuele 14
70054 Giovinazzo (Bari)
Italy
tel./fax +39 080 3357867
mobile +39 347 5016 016
home +39 0883 695055


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