I have a variable with many observations of the sort: 45.34.12 or 66.97.03. These are time measurements (yes I know, ill-considered format for specifying time). I am trying to create a variable that represents the difference between this and another variable with time measurement in the same format (e.g. 45.34.12 - 45.36.06).
Obviously, because these are not real numbers, stata will not be able to perform the arithmetic. Luckily, the numbers before the first decimal are irrelevant, and always the same within an observation (so that the above example is really just 34.12 - 36.06). How can I get stata to uniformly lop off the first two numbers in every observation for these variables, and thus make subtraction of the two columns possible?