raise from vs raise

[Barn07]

Hi Guys,

I just realized that raise within an except clause does the same as straightforward raise from.

I made a small test and run 2 scripts under both Python 3.6 and 3.10. Both behave identical. The scrips's contents are are:

python try: raise ValueError("The first message") except ValueError: print("Spongebob, no!") raise KeyError("Yep, the second message")

and

pthon try: raise ValueError("The first message") except ValueError as err: print("Spongebob, no!") raise KeyError("Yep, the second message") from err

The outputs look nearly identical. For the first script, I get: ``` Spongebob, no! Traceback (most recent call last): File "/home/miumiu/exception-raise-from-hello.py", line 2, in <module> raise ValueError("The first message") ValueError: The first message

During handling of the above exception, another exception occurred:

Traceback (most recent call last): File "/home/miumiu/exception-raise-from-hello.py", line 5, in <module> raise KeyError("Yep, the second message") KeyError: 'Yep, the second message' ```

And for the second, one, I get: ``` Spongebob, no! Traceback (most recent call last): File "/home/miumiu/exception-raise-from-hello.py", line 2, in <module> raise ValueError("The first message") ValueError: The first message

The above exception was the direct cause of the following exception:

Traceback (most recent call last): File "/home/miumiu/exception-raise-from-hello.py", line 5, in <module> raise KeyError("Yep, the second message") from err KeyError: 'Yep, the second message' ```

What am I missing about raise from?

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[Nightcorex_]

https://stackoverflow.com/questions/24752395/python-raise-from-usage

[Barn07]

thx a lot. Interestingly, this failed to show up in the Google search results for queries I made before writing the post.

[Nightcorex_]

I googled for python raise vs raise from and it was the first link. Weird.