Combining two variables into one decimal

[Taylor Walter]

Hi all, I'm sure this is a relatively easy thing to do once you know the syntax, but essentially I have one column with a value with a number 0 through 3, and a second column with a number 0 through 99, and these represent either side of the decimal for respondent GPA. So Column A would have a 2, and Column B would have a 43, and that would represent a GPA of 2.43.

I'm hoping to get them into one variable together, but haven't been able to figure out how yet. Thanks.

[David Benson]

See if this works:

* Example generated by -dataex-. To install: ssc install dataex
clear
input byte(num decimal)
2 92
2 85
3 56
3 42
3 15
3 63
3 75
end

gen gpa = num + (decimal / 100)
list

  +----------------------+
  | num   decimal    gpa |
  |----------------------|
  |   2        92   2.92 |
  |   2        85   2.85 |
  |   3        56   3.56 |
  |   3        42   3.42 |
  |   3        15   3.15 |
  |----------------------|
  |   3        63   3.63 |
  |   3        75   3.75 |
  +----------------------+

[Taylor Walter]

That worked, thanks! Is that easier than doing some type of concatenate command?

[Nick Cox]

No, it's not noticeably easier than concatenation, as that too takes one line, say

* Example generated by -dataex-. To install: ssc install dataex
clear
input byte(num decimal)
2 92
2 85
3 56
3 42
3 15
3 63
3 75
end

gen wanted = string(num) + "." + string(decimal, "%02.0f") 

list, sep(0) 

     +------------------------+
     | num   decimal   wanted |
     |------------------------|
  1. |   2        92     2.92 |
  2. |   2        85     2.85 |
  3. |   3        56     3.56 |
  4. |   3        42     3.42 |
  5. |   3        15     3.15 |
  6. |   3        63     3.63 |
  7. |   3        75     3.75 |
     +------------------------+

The difference lies in what you want. If you want a string, the method is serious. If you want a numeric decimal, David's method is better. Incidentally, you should confirm that say 2.07 is held as 2 and 7 and can be distinguished without error from 2.70 held as 2 and 70.

Note that you could push the string just created through real().