nesting cond()

[Vishal Sharma]

hi All,

I was reading the stata journal version: The Stata Journal (2005) 5, Number 3, pp. 413–420 in order to become familiar with the cond() command, especially to categorize some variables.

In section 4, page 415 , the authors talk about do it yourself categorization using nested cond() command... im just wondering if anyone can share the syntax for this with me, i ve tried everything and couldnt get it to work.

i want to create a variable that is 0 if a=0 & b=0 ; 1 if a=1 & b=0 ; 2 if a==0 & b==1 ; 3 if a==1 & b==1 .. a and b are binary variables i have coded already.

i could use generate and replace commands, but i would like to use the cond() if possible

thanks!

[Nick Cox]

gen wanted = cond(a==0 & b==0, 0, cond(a==1 & b==0, 1, cond(a==0 & b==1, 2, 3)))

I don't favour cond() whatever the context. I would wave a flag for

gen wanted =  0 if a==0 & b==0
replace wanted = 1 if a==1 & b==0
replace wanted = 2  if a==0 & b==1
replace wanted = 3 if a==1 & b==1

or

gen wanted = a + 2 * b

as likely being clearer to more people.