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| Date | Wed, 07 Sep 2011 16:31:37 -0700 |
| From | Gary Herron <gherron@digipen.edu> |
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| Subject | Re: I am confused by |
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On 09/07/2011 03:57 PM, Martin Rixham wrote: > Hi all > I would appreciate some help understanding something. Basically I am > confused by the following: > > >>> a = [[0, 0], [0, 0]] > >>> b = list(a) > >>> b[0][0] = 1 > >>> a > [[1, 0], [0, 0]] > > I expected the last line to be > > [[0, 0], [0, 0]] > > I hope that's clear enough. > > Martin You were expecting the assignment to "b" to create a copy of the original list, and it does, but the copy is only one level deep. So a and b are different lists, but a[i] and b[i] are the same objects for each i. There is a "deepcopy" in the library which may do what you expect. Gary Herron -- Gary Herron, PhD. Department of Computer Science DigiPen Institute of Technology (425) 895-4418
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Re: I am confused by Gary Herron <gherron@digipen.edu> - 2011-09-07 16:31 -0700
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