what is the difference between a = x and a=x[:] in python [duplicate]

Answer 1

Trying to explain:

>>> x = [1,2,3]
>>> a = x
>>> # a is reference to x - a[0] and x[0] are same variable
>>> a[0] = 4 # same as x[0]...
>>> print x # proof
[4, 2, 3]
>>> a = x[:] # a is copy of x
>>> a[2] = 5 # a[2] is not x[2]
>>> print x
[4, 2, 3]
>>> print a
[4, 2, 5]
>>>