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Groups > comp.lang.python > #24852
| From | Mark Lawrence <breamoreboy@yahoo.co.uk> |
|---|---|
| Subject | Re: a problem about "print" |
| Date | 2012-07-04 09:24 +0100 |
| References | (2 earlier) <CAJRADaOt3phGQ=afTy8TOX_qdtGv7zxfzvs2yp1S4GdgdZ=mkQ@mail.gmail.com> <CAEMsKDuejD6UcPrQ9LjiUxEEKjbY8Of7YS8O7kNo65hT3SerbQ@mail.gmail.com> <CAJRADaNqGOF+s-Eq_BNWh+4wsdPcVuttV0zWG1bmw_nyNFHM7Q@mail.gmail.com> <CAEMsKDv8vk0hkjPxd=xe=N7UmQzw9VYY1aTUaf3wk-CALEkJBw@mail.gmail.com> <4FF3F5F5.7070009@boscolini.eu> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.1784.1341390234.4697.python-list@python.org> (permalink) |
@Matteo, @Levi, please don't top post it makes following a thread very difficult, no other comments, TIA. On 04/07/2012 08:51, Matteo Boscolo wrote: > in the code2 > > aList=[1,2,3,4,5,6,7,8,9,10] > aList=str(aList) #<--- here you convert the list in a string > > print aList > print aList[2] #<-- here you are printing the third caracter of the > string '[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]' not the list '[1, 2, 3, 4, 5, > 6, 7, 8, 9, 10]' > > regards > Matteo > > > > Il 04/07/2012 09:28, levi nie ha scritto: >> Hi,Harrison. >> Your method is cool. >> But i doubt this, if bList and aList just are attached to the same >> List when i write bList=aList,but why the output of the following two >> code are different? >> >> code1: >> aList=[1,2,3,4,5,6,7,8,9,10] >> bList=aList >> bList=str(bList) >> print aList >> print aList[2] >> >> code2: >> aList=[1,2,3,4,5,6,7,8,9,10] >> aList=str(aList) >> print aList >> print aList[2] >> >> i'm puzzled now. >> >> 2012/7/4 Harrison Morgan <harrison.morgan@gmail.com >> <mailto:harrison.morgan@gmail.com>> >> >> >> >> On Wed, Jul 4, 2012 at 12:38 AM, levi nie <levinie001@gmail.com >> <mailto:levinie001@gmail.com>> wrote: >> >> that's good,thanks. >> new problem. >> when i write >> bList=aList >> del bList[2] >> bList and aList both change,how can i make aList not changed? >> >> >> >> Lists are mutable. That means that when you do bList = aList, >> you're just creating another reference to aList. They both point >> to the same list, just using different names. You should read up a >> bit on immutable vs. mutable objects. Here's something that I >> found that might explain it a bit better. >> http://henry.precheur.org/python/copy_list >> >> >> >> > > > > > -- Cheers. Mark Lawrence.
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Re: a problem about "print" Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-07-04 09:24 +0100
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