When we define a string, do we cosider it as a list even we don't put it's mark?

Question

for example: str="Hello world!" we don't put it in [ ]

Answer 1

Yes, strings are essentially "lists", in a sense, and can be considered as such in understanding - at least to some extent.
Lists can be iterated upon, indexed, added, multiplied, sliced and so on.
However, there are substantial differences, mainly in handling them. Unlike lists, strings are not pointer-dependent types.
For lists you have:
a = [1, 2, 3]
b = a
a[0] = 0
print (b)
>>>
[0, 2, 3]

Strings do not follow any of that pattern. Of course, you can't assign anything to a string element, as they are immutable (again, unlike lists).