Thomas Passin <li...@tompassin.net> writes: On 5/3/2024 9:56 AM, Johanne Fairchild via Python-list wrote: > How to discover what values produced an exception? Or perhaps---why > doesn't the Python traceback show the values involved in the TypeError? > For instance: > > --8<-------------------------------------------------------->8--- >>>> (0,0) < 4 > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > TypeError: '<' not supported between instances of 'tuple' and 'int' > --8<-------------------------------------------------------->8--- > > It could have said something like: > > --8<-------------------------------------------------------->8--- > TypeError: '<' not supported between instances of 'tuple' and 'int' > in (0,0) < 4. > --8<-------------------------------------------------------->8--- > > We would know which were the values that caused the problem, which would > be very helpful.
In this example it would not help at all to know the actual values. Knowing that you are trying to compare incomparable types is enough. In general, it absolutely can help. The programmer can sometimes recognize where a value of unexpected type came from just by looking at it, allowing her to quickly deduce just what went wrong without further investigation. A good error message shouldn't withhold any information that can _easily_ be included. Debugging is more art than science, so there is no real way to predict what information might prove useful in solving the crime. I emphasized "easily" because of course you have to draw the line somewhere. The fact that Python error messages often fail to mention the actual objects that caused the error has always annoyed me. I've always presumed that for some reason it just wasn't easy to do. And it's never been more than a minor annoyance to me. So the OP is not wrong for wishing for this. Other programming languages do it. Other Python programmers miss it. - Alan -- https://mail.python.org/mailman/listinfo/python-list
