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Groups > comp.lang.python > #65574
| From | Terry Reedy <tjreedy@udel.edu> |
|---|---|
| Subject | Re: Question about `list.insert` |
| Date | 2014-02-06 21:48 -0500 |
| References | <4041bba7-91bc-4803-9150-2fcf14ecb5a9@googlegroups.com> <52F42BDC.7000907@mrabarnett.plus.com> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.6470.1391741345.18130.python-list@python.org> (permalink) |
On 2/6/2014 7:42 PM, MRAB wrote: > On 2014-02-06 23:59, cool-RR wrote: >> Hi, >> >> I'm curious. If I append an item to a list from the left using >> `list.insert`, will Python always move the entire list one item to >> the right (which can be super-slow) or will it check first to see >> whether it can just allocate more memory to the left of the list and >> put the item there, saving a lot of resources? >> > If it needs more space it resizes. It then moves the items. The OP apparently knows that there is usually extra space at the right (end), so that reallocation is usually not needed. He wanted to know whether extra space is also kept at the left (beginning) to make left appends as efficient as right appends. This has been proposed and the answer was to use collections.deque if it really matters. CPython lists are asymmetric re-sizable stacks -- Terry Jan Reedy
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Question about `list.insert` cool-RR <ram.rachum@gmail.com> - 2014-02-06 15:59 -0800
Re: Question about `list.insert` Terry Reedy <tjreedy@udel.edu> - 2014-02-06 19:40 -0500
Re: Question about `list.insert` MRAB <python@mrabarnett.plus.com> - 2014-02-07 00:42 +0000
Re: Question about `list.insert` Terry Reedy <tjreedy@udel.edu> - 2014-02-06 21:48 -0500
Re:Question about `list.insert` Dave Angel <davea@davea.name> - 2014-02-06 21:54 -0500
Re: Question about `list.insert` Roy Smith <roy@panix.com> - 2014-02-06 22:00 -0500
Re: Question about `list.insert` Rustom Mody <rustompmody@gmail.com> - 2014-02-06 19:08 -0800
Re: Question about `list.insert` Tim Chase <python.list@tim.thechases.com> - 2014-02-06 21:11 -0600
Re: Question about `list.insert` Roy Smith <roy@panix.com> - 2014-02-06 22:12 -0500
Re: Question about `list.insert` Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-02-07 17:18 +1300
Re: Question about `list.insert` Chris Angelico <rosuav@gmail.com> - 2014-02-07 14:14 +1100
Re: Question about `list.insert` Chris Angelico <rosuav@gmail.com> - 2014-02-07 14:20 +1100
Re: Question about `list.insert` Rustom Mody <rustompmody@gmail.com> - 2014-02-06 19:29 -0800
Re: Question about `list.insert` Chris Angelico <rosuav@gmail.com> - 2014-02-07 14:45 +1100
Re: Question about `list.insert` Asaf Las <roegltd@gmail.com> - 2014-02-06 19:28 -0800
Re: Question about `list.insert` Dan Stromberg <drsalists@gmail.com> - 2014-02-06 20:52 -0800
Re: Question about `list.insert` Asaf Las <roegltd@gmail.com> - 2014-02-06 21:18 -0800
Re: Question about `list.insert` Peter Otten <__peter__@web.de> - 2014-02-07 09:25 +0100
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