st: using loops in collapse command

[Jocelyn Michael <michaeljocelyn31@gmail.com>]

I am a new stata user and have been trying to write a loop to accomplish a task.

My data looks like this:


id                 Year               Value 1
A               Jan1991             0.92
A               Feb1991             0.93
A               Mar1991             0.24
A               APr1991             0.83
..
..
B               Jan1991             0.67
B               Feb1991             0.45
..

What I am trying to achieve is to write a loop that multiplies value1
for each id and returns one number for each year - sort of like a
collapse command but instead of the sum, I want the product. That is
for A for 1991, (0.92*0.93*0.24*0.83).

Any help is greatly appreciated.

JM.
*
*   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/