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Groups > comp.lang.python > #73899
| From | Mark Lawrence <breamoreboy@yahoo.co.uk> |
|---|---|
| Subject | Re: TypeError expected in an augmented assignment |
| Date | 2014-07-03 13:43 +0100 |
| References | <f1cd7efe-d628-4e96-9ed3-79d9a212f768@googlegroups.com> <mailman.11432.1404356297.18130.python-list@python.org> <55f74a23-95ea-4be1-950d-e57e645dab1a@googlegroups.com> <mailman.11446.1404376617.18130.python-list@python.org> <6ed679b1-c6e1-408e-8167-476b169fa2eb@googlegroups.com> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.11456.1404391406.18130.python-list@python.org> (permalink) |
On 03/07/2014 10:35, candide wrote: > > >> >From that link: >> >> >> >> """ >> >> An augmented assignment expression like x += 1 can be rewritten as x = >> >> x + 1 to achieve a similar, but not exactly equal effect. In the >> >> augmented version, x is only evaluated once. Also, when possible, the >> >> actual operation is performed in-place, meaning that rather than >> >> creating a new object and assigning that to the target, the old object >> >> is modified instead. >> >> """ >> >> >> >> The significance here is that the augmented assignment may not >> >> necessarily be at all comparable to the non-augmented version, but >> >> ought to have *approximately* the same *intention*. > > > This is not my reading. > > > > >> >> of situations where the two will differ, eg when there are multiple >> >> references to the same object: >> >> >> >>>>> a = b = [1,2] >> >>>>> a += [3] >> >>>>> a,b >> >> ([1, 2, 3], [1, 2, 3]) >> >>>>> a = a + [4] >> >>>>> a,b >> >> ([1, 2, 3, 4], [1, 2, 3]) >> >> > > OK but this behavior is in conformance with the Reference Manual (cf. your quote above : "when possible, the actual operation is performed in-place"). This is not my point because the doc explictly claims that "an augmented assignment [...] performs the binary operation specific to the type of assignment on the two operands". > To get the wording changed to satisfy yourself, either raise an issue on the bug tracker at bugs.python.org and attach a patch file, or send an email with suggested wording to docs@python.org. -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com
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TypeError expected in an augmented assignment candide <c.candide@laposte.net> - 2014-07-02 19:39 -0700
Re: TypeError expected in an augmented assignment Terry Reedy <tjreedy@udel.edu> - 2014-07-02 22:57 -0400
Re: TypeError expected in an augmented assignment candide <c.candide@laposte.net> - 2014-07-03 00:51 -0700
Re: TypeError expected in an augmented assignment Chris Angelico <rosuav@gmail.com> - 2014-07-03 18:36 +1000
Re: TypeError expected in an augmented assignment candide <c.candide@laposte.net> - 2014-07-03 02:35 -0700
Re: TypeError expected in an augmented assignment Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-07-03 13:43 +0100
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