[Python-Dev] odd "tuple does not support assignment" confusion...
Alex A. Naanou
alex.nanou at gmail.com
Sat Mar 3 00:06:33 CET 2012
Just stumbled on a fun little thing:
We create a simple structure...
l = (,)
Now modify the list, and...
l += 
## Traceback (most recent call last):
## File "F:\work\ImageGrid\cur\ImageGrid\src\test\python-bug.py",
line 17, in <module>
## l += 
## TypeError: 'tuple' object does not support item assignment
Tested on 2.5, 2.7, 3.1, PyPy1.8 on win32 and 2.7 on x86-64 Debian
(just in case).
I was expecting this to succeed, is this picture wrong or am I missing
...am I really the first one to try and modify a list within a tuple directly?!
It's even more odd that I did not try this myself since first started
with Python back in 99 :)
I could not google this "feature" out either...
BTW, It is quite trivial (and obvious) to trick the interpreter to get
the desired result...
e = l
e += 
P.S. the attachment is runnable version of the above code...
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