Let's say I want to change the content of string local named asdf from q to 2. I tried this

Code:
. local asdf "q"

. display("`asdf'")
q

. local asdf subinstr(`asdf',"q","2")

. display("`asdf'")
subinstr(q,

As you can see, the last line does not produce what I expect. I expected 2 will come out. How can I solve this problem?