List and it's references in Python -

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• how clone or copy list? 14 answers

i going through python doc when came upon lists , confused these :-

1.

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

how can appending a change both a , b using a=[] changes a , not b.

2. as know id(a) != id(a[:]) why doing a[:]=[] changes a?

thank you.

references variables point objects in memory. doing

b = 

is making b point same memory location a pointing.

this means through both variables b , a can modify same contents in memory, , explains "why modifying b modifies a".

now, when

a = []  

you creataing new empty list in memory , making a pointing it...

of course general explanation, think gives intuition.