missing values

[Timea De Wispelaere]

Hello, I wanted to create a dummy based on a certain variable, but only if that variable had a value (so no . or a blank cell). My question is now whether or not stata also recognizes an empty cell as a missing value because this is how I would code it:

generate industry08 = twodigitsNACE == 08 if !missing(twodigitsNACE)

so my question is, if there are cells containing . or blank cells for TWODIGITSNACE, does stata returns a dot in both cases?
And also related with this question: if I run a regression, does stata treats empty cells and cells with . the same, so does stata eliminates these from the regression?

kind regards,
Timea

[Nick Cox]

A string variable can’t be used in a regression, so empty strings make no difference any way.

Please show us a data example for twodigitsNACE.