Generating & replacing new variable

[Alan Jeddi]

Hi there,

I have a variable called lop and another variable called age

I would like to generate a new variable, called age_tied_to_lop, where AGE only has a value if LOP has a value (ie, if LOP = . then I also want my age_tied_to_lop to be coded as missing .)

I tried the following code, but its not really working:

gen age_tied_to_lop = .

replace age_tied_to_lop = age if lop>0

But I don't want to replace if lop>0; I want to replace only if lop actually has a value (ie, is any value other than .)

Thanks for any help

[Rich Goldstein]

since missing is the highest value, it is greater than 0; your code won't do what you want; instead, as your second command, try this

replace age_tied_to_lop = age if lop<.

you don't really give enough info to know if this is sufficient (please read the FAQ)

[Marcos Almeida]

You may try to use - if !missing(lop) - for that matter.