list automatically changing without reference

Asked Feb 01 '19 at 00:14

Active Feb 02 '19 at 11:40

Viewed 65 times

I have a list of links which i am getting from BeuitfulSoup object, after links2=links1then i edited links1 ,but links2 got changed as well so i test in IDLE. Example of a list which i want to modify but keep the original one intact, how can i do it?

a=[1,2,3]
b=a
a.append(4)
print b

Output

[1, 2, 3, 4]

i want b to stay [1,2,3]

edited Feb 01 '19 at 00:50

asked Feb 01 '19 at 00:14

wishmaster

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`b = a[:]` or `b = list(a)` – iz_ Feb 01 '19 at 00:36
@Tomothy32 does this create a new list or just copies the reference of original one? – wishmaster Feb 01 '19 at 00:51
Have you tried it? – iz_ Feb 01 '19 at 01:41
I have reopened the question because it is no longer a duplicate of _that_ question, but it is still a duplicate as referenced by @AndrasDeak. – Selcuk Feb 02 '19 at 11:35
For additional info see a good tutorial and https://nedbatchelder.com/text/names.html – Andras Deak -- Слава Україні Feb 02 '19 at 11:35
@Selcuk Why not just replace the duplicate target? Reopening just so we can reclose seems like a waste of resources. – tripleee Feb 02 '19 at 11:40
1

@tripleee I saw the post when it was bumped by the unhammer. My suggestion came after. I suspect if Selcuk knew about the better target they'd have edited the dupe list instead. – Andras Deak -- Слава Україні Feb 02 '19 at 12:03
2

Ah okay, thanks for clarifying. – tripleee Feb 02 '19 at 12:04
1

@AndrasDeak thanks a lot great reference, really explains a lot of what actually happens behind the scenes. – wishmaster Feb 02 '19 at 15:59

list automatically changing without reference

0 Answers0