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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:
side=[5]
eva=side
print(str(side) + " side before")
print(str(eva) + " eva before")
eva.remove(5)
print(str(side) + " side after")
print(str(eva) + " eva after")
This yields:
[5] side before
[5] eva before
[] side after
[] eva after
Why does the remove command also affects the list 'side'? What can I do to use a copy of 'side', without modifying the list?
Thank you very much
Edit: Thank you very much for the good and comprehensible answers!
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To convert a list to a string, use Python List Comprehension and the join() function. The list comprehension will traverse the elements one by one, and the join() method will concatenate the list's elements into a new string and return it as output.
The remove() function removes the first matching value from the list. The pop() function is used to return the removed element from the list. The del() function is used to delete an element at a specified index number in the list.
The remove() method is one of the ways you can remove elements from a list in Python. The remove() method removes an item from a list by its value and not by its index number.
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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