Interaction variable not working

[Anders Hindsholm]

I tried running a regression with an interaction variable, the code is as follows:

reg voteA prtystrA expendA expendB expendA#expendB

And i get the following error message:

expendA: factor variables may not contain noninteger values

How do i circumvent this issue?

[daniel klein]

The notation

varname#varname

implies

i.varname#i.varname

that is the interaction of two categorical variables. If your variables are continuous, type

c.varname#c.varname

If your variables are supposed to be categorical, recorde to (positive) integer values.