Why doesn't Python (error msg) tell me WHAT the actual (arg) values are ?

[avi.e.gross at gmail.com]

Hen or Hanna,

You keep asking WHY which may be reasonable but hard or irrelevant in many
cases.

I find the traceback perfectly informative.

It says you asked it to print NOT just "a" but "a + 12" and the error is
coming not from PRINT but from trying to invoke addition between two objects
that have not provided instructions on how to do so. Specifically, an object
of type str has not specified anything to do if asked to concatenate an
object of type int to it. And, an object of type int has not specified what
to do if asked to add itself to an object of type str to the left of it.
Deeper in python, the objects have dunder methods like __ADD__() and
___RADD__() to invoke for those situations that do some logic and decide
they cannot handle it and return an exception of sorts that ends up
generating your message.

If you want to know what "a" has at the moment, ask for just it, not adding
twelve to it. Perhaps you should add a line above your print asking to just
print(a).

Before you suggest what might be helpful, consider what it might mean in a
complex case with lots of variables and what work the interpreter might have
to do to dump the current values of anything relevant or just ANYTHING.

The way forward is less about asking why but asking what to do to get what
you want, or realize it is not attained the way you thought.

Avi

-----Original Message-----
From: Python-list <python-list-bounces+avi.e.gross=gmail.com at python.org> On
Behalf Of Hen Hanna
Sent: Wednesday, February 22, 2023 3:05 PM
To: python-list at python.org
Subject: Why doesn't Python (error msg) tell me WHAT the actual (arg) values
are ?


          >  py   bug.py
       Traceback (most recent call last):
         File "C:\Usenet\bug.py", line 5, in <module>
                     print( a + 12 )
          TypeError: can only concatenate str (not "int") to str


Why doesn't  Python (error msg) do the obvious thing and tell me
            WHAT   the actual   (offending,  arg)  values are ?

In many cases, it'd help to know what string the var  A  had  ,   when the
error occurred.
             ------------  i wouldn't have to put      print(a)     just
above,  to see.




( pypy    doesn't do that either,   but Python makes programming (debugging)
so easy that i hardly feel any inconvenience.)
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