Splitting string to individual characters using slicing

Question

I'm confused how the following python code works to split a string to individual characters using b[:0] = a. Shouldn't it be just b = ['abc']?

a='abc'
b=[]
b[:0]=a
print(b)

output:

b=[a,b,c]

Answer 1

This is because the list constructor can be used to split any iterables, such as strings.

You do not even need [:0],

list(a) # ['a', 'b', 'c']

or,

b = []
b[:] = a # ['a', 'b', 'c']

Answer 2

According to Python Doc whenever left side of assignment statement is slicing, python do __setitem__ so in this case it put right side items in the beginning of slicing. take a look at this example:

>>> a = [1,2,3,4]
>>> b = [5,6,7,8]
>>> b[3:5] = a
>>> print(b)
[5, 6, 7, 1, 2, 3, 4]