I read in a dataset that includes many columns of categorical variables denoted by '1', '2', ...

1) I cannot condition on the values directly -- br if variable=='2' will give error "'2' invalid name"
2) I cannot use destring to convert to numeric (they all end up as missing if I force it)
3) I've attached screenshots of what the codebook and tab commands show

Any ideas for how to either a) convert these to their corresponding integers or b) be able to condition on the string values

I am using Stata 16.