numeric values in a string

[Adrienne Wold]

I have a string variable "occupation" that records all values selected from a choice list. For example, when occupations 3 and 23 are selected, the occupation variable is "3 23".

I want to merge two codes from the choice list together, and therefore replace all values where "2" is included as an occupation with "1". If "1" is already included as an occupation, I only want to remove "2".

I use

gen has_2' = regexs(0) if(regexm(occupation "[2]"))

to identify when a 2 is present but I am not sure how to only match "2"s when they are not 2s as a part of 20-9.

[Nick Cox]

This is the problem solved by subinword().

* Example generated by -dataex-. For more info, type help dataex
clear
input str42 whatever
"2 21 22"
"9 2 3"  
"1 2 3"
end

clonevar newvar = whatever 
replace newvar = subinword(newvar, "2", "",  1) if strpos(" " + newvar + " ", " 1 ")
replace newvar = subinword(newvar, "2", "1", 1)   

list 

     +--------------------+
     | whatever    newvar |
     |--------------------|
  1. |  2 21 22   1 21 22 |
  2. |    9 2 3     9 1 3 |
  3. |    1 2 3      1  3 |
     +--------------------+