The problem of python Recursion and the question of list remove

problem description

Why does the operation on code_3 affect the value of code_2?
originally there is no relationship between the two.

the environmental background of the problems and what methods you have tried

I personally understand that I assign values in the first few lines of code and operate in the for loop without affecting the value of code--2, but my debug found that the value of code_2 has also changed. no, no, no.
I don"t know why this happens. Isn"t Python translated line by line? no, no, no.

related codes

/ / Please paste the code text below (do not replace the code with pictures) 

code=[1,2,3,4,5]
code_1=code
-sharp 
for i in code:  -sharp code   "A"
    print(i)
    for k in code_1:
        print(k)
    code_1.remove(i)

what result do you expect? What is the error message actually seen?

what I expect is that code and code_1 do not affect each other, but I have deleted the code1 element, why the code element will also be deleted.

Python
Aug.01,2021

if you don't want to be changed, you need to copy, not assign
such as 

code_2=code.copy()
After

assignment, the reference to the object is a 

>>> code=[1,2,3,4]
>>> id(code)
4552379656
>>> code2=code
>>> id(code2)
4552379656

you can see that their ID is equal, pointing to the same address (object) in memory. Changing one naturally affects another
copy or rebuilding one with list or [:] methods, id is different, and changing one naturally does not affect the other.

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MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-16de5f8-2b54e.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-16de5f8-2b54e.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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