Python: Confused with list.remove

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野趣味
野趣味 2021-01-11 18:27

I\'m very new to Python, so sorry for the probably simple question. (Although, I spent now 2 hours to find an answer)

I simplified my code to illustrate the problem

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  • 2021-01-11 18:57

    dusan's answer is correct, and is a clever approach, but I think it breaks the Zen of Python guideline that "Explicit is better than implicit."

    A far more common pattern I've seen to ensure an item is a deepcopy is with the copy module.

    >>> import copy
    >>> eva = copy.copy(side)
    
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  • 2021-01-11 19:05

    Python has "things" and "names for things". When you write

    side = [5]
    

    you make a new thing [5], and give it the name side. When you then write

    eva = side
    

    you make a new name for side. Assignments are just giving names to things! There's still only one thing [5], with two different names.

    If you want a new thing, you need to ask for it explicitly. Usually you would do copy.copy(thing), although in the case of lists there's special syntax thing[:].

    FYI "things" are usually called "objects"; "names" are usually called "references".

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  • 2021-01-11 19:14

    eva and side refer to the same list.

    If you want to have a copy of the list:

    eva = side[:]
    

    You can read more about copying lists in this article: Python: copying a list the right way

    Edit: That isn't the only way to copy lists. See the link posted in the first comment of this answer.

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