st: joining strings

[Kevin McConeghy <kevinmcconeghy@gmail.com>]

Hello users,

I have a dataset with ~2.2 mill obs like so:

obs
id        stringvar    + other variables
1          x
1          y
1          z
2          a
3          d
4          g
4          h

I was trying to combine the stringvar to collapse and make id a unique
key, like so:

id         stringvar
1          xyz
2          a
3          d
4          gh

with the following code:

quietly by id: gen x_ = cond(_N==1,0,_n)
egen x = concat(x_), p(_)
drop x_

reshape wide stringvar, i(id) j(x) string
egen str244 all_stringvar=concat(x1, x2, x3....)

Which worked for one quarter of data, but it takes a lot of computer
power with 1.9 obs and up to 100 unique string var for 1 obs
My computer wont calculate it for the whole dataset because it runs
out of memory

Is there some way to skip the reshape step and join string variables
by specifying the same id?:
egen stringvar_all = concat(stringvar), by id

Thanks for any help,
Kevin
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/