Sort order for strings with blanks - apply only observed value to all subjects by id

[Graham Wells]

Hello,
I have data in this form

id	string	string2
1
1	N
1		N
2
2
2
3
3
3	N
3
3

here is the dataex

* Example generated by -dataex-. To install: ssc install dataex
clear
input str1 id str1 string str1 string2
"1" "" ""
"1" "N" ""
"1" "" "N"
"2" "" ""
"2" "" ""
"2" "" ""
"3" "" ""
"3" "N" ""
"3" "" ""
end

and I want to convert string and string2 to be:

id	string	string2
1	N	N
1	N	N
1	N	N
2
2
2
3	N
3	N
3	N
3	N
3	N

But when I sort by id and string and try to apply to value to all id, the string is sorted with missing values first

bysort id (string): replace string=string[1]

but as I said the blanks are sorted first and this applies the blank to all each id. Is there a way to reverse the sort order? gsort does not seem to work for strings
any help would be great

[Andrew Musau]

foreach var of varlist string*{
      bys id (`var'): replace `var'=`var'[_N]
}

Res:

. l, sepby(id)

     +-----------------------+
     | id   string   string2 |
     |-----------------------|
  1. |  1        N         N |
  2. |  1        N         N |
  3. |  1        N         N |
     |-----------------------|
  4. |  2                    |
  5. |  2                    |
  6. |  2                    |
     |-----------------------|
  7. |  3        N           |
  8. |  3        N           |
  9. |  3        N           |
     +-----------------------+

[Graham Wells]

Yes, that worked thank you