How to order within a string containing letters and numbers?

[Lucian Liu]

Dear all,

I have a string variable, it looks like:

A1B5B3H7D2

Now I need to order it by every two digits. The desirable results will be:

A1B3B5D2H7

Thanks a lot!

[Joseph Coveney]

You might want to start by Googling first normal form.

[Nick Cox]

This works with your example:

clear 
input str8 whatever 
"A1B5B3H7D2"
end 

forval j = 1/4 { 
    gen  w`j' = substr(whatever, `j' * 2 - 1, 2) 
} 

* install from Stata Journal 
rowsort w?, generate(W1 W2 W3 W4) 
egen WHATEVER = concat(W?) 

list 

     +-------------------------------------------------------------+
     | whatever   w1   w2   w3   w4   W1   W2   W3   W4   WHATEVER |
     |-------------------------------------------------------------|
  1. | A1B5B3H7   A1   B5   B3   H7   A1   B3   B5   H7   A1B3B5H7 |
     +-------------------------------------------------------------+

[Lucian Liu]

This works with your example:

clear
input str8 whatever
"A1B5B3H7D2"
end

forval j = 1/4 {
gen w`j' = substr(whatever, `j' * 2 - 1, 2)
}

* install from Stata Journal
rowsort w?, generate(W1 W2 W3 W4)
egen WHATEVER = concat(W?)

list

+-------------------------------------------------------------+
| whatever w1 w2 w3 w4 W1 W2 W3 W4 WHATEVER |
|-------------------------------------------------------------|
1. | A1B5B3H7 A1 B5 B3 H7 A1 B3 B5 H7 A1B3B5H7 |
+-------------------------------------------------------------+

Thanks a ton, Nick. That helps!