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Python Python Collections (2016, retired 2019) Tuples Introduction To Tuples

Posted by john larson
john larson
16,594 Points

modifying a list in a tuple, odd behavior

Kenneth was talking about modifying lists inside tuples so I was playing around with that. I got an error (which didn't really surpise me) but it did what I asked anyway (which really confuses me)

>>> tup_list
(1, 2, [1, 2, 3, 4, 5, 6])
>>> tup_list[2] += 7,8,9
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'tuple' object does not support item assignment # error here
>>> tup_list
(1, 2, [1, 2, 3, 4, 5, 6, 7, 8, 9]) # adds 7,8,9 even though it says it can't
>>>

1 Answer

Steven Parker
Steven Parker
231,275 Points
Steven Parker
Steven Parker
231,275 Points

:point_right: It appears to be a spurious error message.

I did get the same thing when I tried. But, you can get the same result with no error by doing this:

tup_list[2].extend([7, 8, 9])
john larson
john larson
16,594 Points

Thanks Steve.