On 2020-07-31 14:15, Jon Ribbens via Python-list wrote:
On 2020-07-31, Stefan Ram <r...@zedat.fu-berlin.de> wrote:
You can write
|>>> 1,+2,
|(1, 2)
, but not
|>>> (1,)+2,
|TypeError: can only concatenate tuple (not "int") to tuple
. Why? (Python 3.9)
For the obvious reason, as indicated by the error message?
What are you expecting these expressions to mean?
(For some reason, I haven't received Stefan's original post.)
It's all to do with operator precedence.
The '+' has a higher precedence than the ',', so:
1,+2,
is parsed as:
(1),(+2),
NOT as:
(1,)+(2,)
although they happen to give the same answer.
On the other hand:
(1,)+2,
is parsed as:
((1,)+2),
which results in a TypeError.
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