Yes,you're right. I got it now.I mistaked that aList also had be changed in code1 before. Thanks a lot.
2012/7/4 Matteo Boscolo <matteo.bosc...@boscolini.eu> > 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.mor...@gmail.com> > >> >> >> On Wed, Jul 4, 2012 at 12:38 AM, levi nie <levinie...@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 >> > > > > > > > -- > http://mail.python.org/mailman/listinfo/python-list > >
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