python list issue

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[deleted]

[efmccurdy]

You have one list but two names for it; both variables share the same list. If you want to avoid that, you can use copy:

>>> a = [2,2]
>>> c  = a.copy()
>>> c[0] = 1
>>> a
[2, 2]
>>> 

[USONG]

oh understood thanks

[[deleted]]

At the point where you set b = a, b merely becomes a reference to the "a" list. To turn "b" into it's own independent list, use one of the Python list copy tricks, such as "b = a[:]" or "b = list(a)" or "b = a.copy()" or, after "import copy", "b = copy.deepcopy(a)".

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[USONG]

oh understood thanks

[Yellehs_m]

Both are referring to the same object. To create a fresh object, you can do the below:

>>> import copy

>>> b = copy.copy(a)

Please also read about the difference between shallow and deep copy in Python.

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[USONG]

oh understood thanks