A vector argument to sprintf

[Niels Henrik Bruun]

Hi
I've become quite fond of using sprintf.
And increasingly often I find myself with a vector of arguments I have to split up in a tedious way.

So far as I can get with my limited ressources the only thing I can do in Stata is:

v = 12,23,31
sprintf("%f, %f, %f", v[1], v[2], v[3])

Is there a smart way of doing something like:

sprintf("%f, %f, %f", v)

[Christophe Kolodziejczyk]

Maybe you could try mm_matlist() function from the moremata package (author: Benn Jann) , if the purpose is to control the format of your vector or matrix.

[Niels Henrik Bruun]

Hi Christophe
Thank you.
A fine suggestion and I will definitely look into it.
But I also often use string vectors/matrices.
I admit that I didn't provide a proper example, sorry.
Is there something similar for string vectors/matrices?

[Christophe Kolodziejczyk]

ok, I overlooked the string part of your post. Isn't there some inspiration you could get from
mm_matlist()'s code?

[Niels Henrik Bruun]

Probably
I'll look into it.
The documentation says it uses -sprintf-, so maybe I'm lucky.

[Mead Over]

Has anyone yet created a version of Ben Jann 's mm_matlist() that would accept a string, rather than real, matrix?

[John Mullahy]

re: #6, I would often find this useful.

I occasionally use a brute-force method based on my user-written function invtokmatstr along with Mata's -display- function.

/* returns Nx1 matrix of rows' invtokens of Nxk string matrix z      */
/* string scalar s defines the separators between the rows' elements */
/* (see help invtokens)                                              */

function invtokmatstr(z,|string scalar s) {
string matrix c
c=J(0,1,"")
for (j=1;j<=rows(z);j++) {
 c=c\invtokens((z[j,.]),s)
}
return(c)
}

For example

mata

sm=J(10,4,"abc")

sm

ism=invtokmatstr(sm, ", ")

ism

display(ism)

end

which yields

. mata
------------------------------------------------- mata (type end to exit) ---------------------------
:
: sm=J(10,4,"abc")

:
: sm
          1     2     3     4
     +-------------------------+
   1 |  abc   abc   abc   abc  |
   2 |  abc   abc   abc   abc  |
   3 |  abc   abc   abc   abc  |
   4 |  abc   abc   abc   abc  |
   5 |  abc   abc   abc   abc  |
   6 |  abc   abc   abc   abc  |
   7 |  abc   abc   abc   abc  |
   8 |  abc   abc   abc   abc  |
   9 |  abc   abc   abc   abc  |
  10 |  abc   abc   abc   abc  |
     +-------------------------+

:
: ism=invtokmatstr(sm, ", ")

:
: ism
                         1
     +----------------------+
   1 |  abc, abc, abc, abc  |
   2 |  abc, abc, abc, abc  |
   3 |  abc, abc, abc, abc  |
   4 |  abc, abc, abc, abc  |
   5 |  abc, abc, abc, abc  |
   6 |  abc, abc, abc, abc  |
   7 |  abc, abc, abc, abc  |
   8 |  abc, abc, abc, abc  |
   9 |  abc, abc, abc, abc  |
  10 |  abc, abc, abc, abc  |
     +----------------------+

:
: display(ism)
abc, abc, abc, abc
abc, abc, abc, abc
abc, abc, abc, abc
abc, abc, abc, abc
abc, abc, abc, abc
abc, abc, abc, abc
abc, abc, abc, abc
abc, abc, abc, abc
abc, abc, abc, abc
abc, abc, abc, abc

:
: end

I have sometimes thought that expanding the capabilities of Mata's -display- function to accommodate general string matrix arguments instead of just string column vectors would be valuable.

[Ben Jann]

Hi, coding invtokmatstr() as follows would be much more efficient.

mata:
string colvector invtokmatstr(string matrix z, | string scalar s)
{
    real scalar      j
    string colvector c
    
    j = rows(z)
    c = J(j,1,"")
    for (;j;j--) {
        c[j] = invtokens((z[j,.]),s)
    }
    return(c)
}
end

Setting up a matrix of the correct size upfront and then filling it in is much less work for the computer than creating the matrix over an over, each time adding a row.
ben

[Ben Jann]

Just a few minor tweaks were necessary to add support for string matrices in mm_matlist(). I will update moremata on GitHub tomorrow (need access to a different computer that still has some old Stata versions installed that are used to compile moremata).

[Ben Jann]

The new moremata version with string support in mm_matlist() is now available on GitHub, type

. net install moremata, replace from(https://raw.githubusercontent.com/benjann/moremata/master/)

to update moremata on your system.

Don't know how useful string support in mm_matlist() really is, but here are some examples.

. mata
: sm = J(4,3,"abc")

: sm
         1     2     3
    +-------------------+
  1 |  abc   abc   abc  |
  2 |  abc   abc   abc  |
  3 |  abc   abc   abc  |
  4 |  abc   abc   abc  |
    +-------------------+

: mm_matlist(sm)
         1     2     3
    +-------------------+
  1 |  abc   abc   abc  |
  2 |  abc   abc   abc  |
  3 |  abc   abc   abc  |
  4 |  abc   abc   abc  |
    +-------------------+

: mm_matlist(sm, "%s", 0)
        1     2     3
  1   abc   abc   abc
  2   abc   abc   abc
  3   abc   abc   abc
  4   abc   abc   abc

: mm_matlist(sm, "%s", 2)
    |    1     2     3
----+-----------------
  1 |  abc   abc   abc
  2 |  abc   abc   abc
  3 |  abc   abc   abc
  4 |  abc   abc   abc

: mm_matlist(sm, "%~8s", 3, "row ":+strofreal(1::rows(sm)),
>     "column ":+strofreal(1..cols(sm)))
-----------------------------------------
        |  column 1   column 2   column 3
--------+--------------------------------
  row 1 |     abc        abc        abc  
  row 2 |     abc        abc        abc  
  row 3 |     abc        abc        abc  
  row 4 |     abc        abc        abc  
-----------------------------------------

: end

ben