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

[Thomas Passin]

On 2/22/2023 6:46 PM, Hen Hanna wrote:
> On Wednesday, February 22, 2023 at 12:05:34 PM UTC-8, Hen Hanna wrote:
>>> 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.)
> 
> 
> 
> i  see that my example   would be clearER  with this one-line  change:
> 
> 
>                    >  py   bug.py
> 
>                     Traceback (most recent call last):
> 
>                    File "C:\Usenet\bug.py", line 5, in <module>
>                                           map( Func,    fooBar(  X,  Y,  X +  Y  ))
>   
>                     TypeError: can only concatenate str (not "int") to str
> 
> 
> i hope that   NOW   a few of you  can  see this as a genuine,  (reasonable)  question.

It tells me to go look at the function definition and how it's being 
invoked.  Even if I knew which of (X, Y) was an int and which a str, I'd 
still need to do that.

Or you could add type annotations to your code and run mypy on it...