Variable with negative values

[Johan Anderson]

Hey,

I'm stuck on a simple thing and would really need some help. I have a non-numeric variable ranging from -5 to +5. I want to make it into only positive values so that -5 represents 1 and -4 represents 2 etc. Does anyone know how to do this easily? I suppose I first encode it but when I have done so and then recoded the variables to positive ones i only get values between 6 to 10 even though I recoded -5 to 1.

/Johan

[Nick Cox]

. clear

. set obs 11
number of observations (_N) was 0, now 11

. range whatever -5 5

. gen wanted = whatever + 6

. list, sep(0)

     +-------------------+
     | whatever   wanted |
     |-------------------|
  1. |       -5        1 |
  2. |       -4        2 |
  3. |       -3        3 |
  4. |       -2        4 |
  5. |       -1        5 |
  6. |        0        6 |
  7. |        1        7 |
  8. |        2        8 |
  9. |        3        9 |
 10. |        4       10 |
 11. |        5       11 |
     +-------------------+

[William Lisowski]

In post #2 Nick Cox overlooked your hint that your input variable is stored as a string.

He also overlooked your reference to using encode to convert the string to a numeric variable. That was a mistake on your part. The encode command is designed for assigning numerical codes to non-numeric strings like "France", "Germany", "United States". The output of help encode instructs us

Do not use encode if varname contains numbers that merely happen to be stored as strings; instead, use generate newvar = real(varname) or destring; see real() or [D] destring.

In the example below, I start with your numbers from -5 to +5 stored in a string variable, use destring to create a numeric variable, then apply Nick's approach to transform them from [-5,+5] to [0,11].

. destring x_string, generate(x_number)
x_string: all characters numeric; x_number generated as byte

. generate wanted = x_number+6

. list, clean noobs

    x_string   x_number   wanted  
          -5         -5        1  
          -4         -4        2  
          -3         -3        3  
          -2         -2        4  
          -1         -1        5  
           0          0        6  
          +1          1        7  
          +2          2        8  
          +3          3        9  
          +4          4       10  
          +5          5       11  

. describe *

              storage   display    value
variable name   type    format     label      variable label
------------------------------------------------------------------------------------------------
x_string        str4    %9s                   
x_number        byte    %10.0g                
wanted          float   %9.0g                 

.

[Nick Cox]

#3 Good point and note also

gen wanted = real(x_string) + 6