keep if either variable is not empty

[Jarvine Xie]

Hi all,
I am very new to Stata. I have a few variables, and two of them are string: open_on, close_on. I want to keep only the sample where open_on is filled or close_on is filled or both are filled. I know my question sounds very easy...but I just do not how to convert it into a conditional code.
I tried:

drop if opened_on == "" | closed_on == ""

But only observations where both are filled are kept. I am not sure why.
I would deeply appreciate your assistance!

[George Ford]

keep if (opened_on != "" | closed_on != "")

[Bruce Weaver]

If I follow, you want to drop rows where both variables == "", so you need &, not |.

clear
input str1(opened_on closed_on)
"a" "b"
"" "c"
"d" ""
"" ""
end

* keep only the rows where open_on is filled or close_on is filled
* or both are filled
generate byte tokeep = opened_on != "" | closed_on != ""
* drop rows where both variables == ""
generate byte todrop = opened_on == "" & closed_on == ""
list

Output from -list-:

. list

     +---------------------------------------+
     | opened~n   closed~n   tokeep   todrop |
     |---------------------------------------|
  1. |        a          b        1        0 |
  2. |                   c        1        0 |
  3. |        d                   1        0 |
  4. |                            0        1 |
     +---------------------------------------+

Note: Crossed with George Ford's response in #2.

[Jarvine Xie]

thanks guys! solved