Expand something like x1-x10 in mata to x1 x2...x10

[Wen Qin]

Dear all,

I want to expand a macro in stata comtain something like "x1-x10"or "bs*" in mata to x1 x2...x10 or "bs1 bs2 ..." and print then only some of them. by order.

I tried st_macroexpand() , it did not work.

Thanks for any help!

[Niels Henrik Bruun]

Hi
I would go for something like:

. sysuse auto
(1978 Automobile Data)

. mata
------------------------------------------------- mata (type end to exit)
: stata("unab x : make-trunk")

: tokens("`x'")
              1          2          3          4          5          6
    +-------------------------------------------------------------------+
  1 |      make      price        mpg      rep78   headroom      trunk  |
    +-------------------------------------------------------------------+

using the -unab- command in Stata.

[Frank Erickson]

mata desc x* prints Mata objects matching that pattern, though I know no way to store the results in a string vector.

A custom function could be used to enumerate x1..x10, but I don't know a way to search to see if they exist.

function stringseq(pre,nums){
  n = length(nums)
  x = J(1,n,"")
  for(i=1;i<=n;i++) x[i] = pre + strofreal(nums[i])
  x
}

stringseq("x",2::5)
        1    2    3    4
    +---------------------+
  1 |  x2   x3   x4   x5  |
    +---------------------+

I'd be interested in finding an approach that both (i) searches for a pattern in the Mata workspace and (ii) enumerates the results like ds does in Stata.