Hi all,
I have the 16 loops below, that I want to compress it:
HTML Code:

mat Y = J(21, 32, .)
forvalues i=1/21 {
      qui sum x if c`i'==1 & a1==1
      matrix Y[`i',1] = r(min)
      matrix Y[`i',2] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a2==1
      matrix Y[`i',3] = r(min)
      matrix Y[`i',4] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a3==1
      matrix Y[`i',5] = r(min)
      matrix Y[`i',6] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a4==1
      matrix Y[`i',7] = r(min)
      matrix Y[`i',8] = r(max)
      }


forvalues i=1/21 {
      qui sum x if c`i'==1 & a5==1
      matrix Y[`i',9] = r(min)
      matrix Y[`i',10] = r(max)
      }


forvalues i=1/21 {
      qui sum x if c`i'==1 & a6==1
      matrix Y[`i',11] = r(min)
      matrix Y[`i',12] = r(max)
      }


forvalues i=1/21 {
      qui sum x if c`i'==1 & a7==1
      matrix Y[`i',13] = r(min)
      matrix Y[`i',14] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a8==1
      matrix Y[`i',15] = r(min)
      matrix Y[`i',16] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a9==1
      matrix Y[`i',17] = r(min)
      matrix Y[`i',18] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a10==1
      matrix Y[`i',19] = r(min)
      matrix Y[`i',20] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a11==1
      matrix Y[`i',21] = r(min)
      matrix Y[`i',22] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a12==1
      matrix Y[`i',23] = r(min)
      matrix Y[`i',24] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a13==1
      matrix Y[`i',25] = r(min)
      matrix Y[`i',26] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a14==1
      matrix Y[`i',27] = r(min)
      matrix Y[`i',28] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a15==1
      matrix Y[`i',29] = r(min)
      matrix Y[`i',30] = r(max)
      }

forvalues i=1/21 {
      qui sum x if c`i'==1 & a16==1
      matrix Y[`i',31] = r(min)
      matrix Y[`i',32] = r(max)
      }
I tried:
HTML Code:
local j = 1
local k = 1
forvalues i=1/21 {
      qui sum x if c`i'==1 & a`j'==1
      matrix Y[`i',`k'] = r(min)
      local ++k
      matrix Y[`i',`k'] = r(max)
      local ++k
      local ++j
      
      }
and
HTML Code:
local j = 1
local k = 1
forvalues i=1/21 {
      qui sum x if c`i'==1 & a`j'==1
      matrix Y[`i',`k'] = r(min)
      local ++k
      matrix Y[`i',`k'] = r(max)
      local ++k
      local ++j
      
      }
But they are not correct.
I would appreciate if some one can help me with it.

Best,
Emma