Importing with dot notation

import a.b imports b into the namespace a, you can access it by a.b . Be aware that this only works if b is a module. (e.g. import urllib.request in Python 3)

from a import b however imports b into the current namespace, accessible by b. This works for classes, functions etc.

Be careful when using from - import:

from math import sqrt
from cmath import sqrt

Both statements import the function sqrt into the current namespace, however, the second import statement overrides the first one.

When you're putting that dot in your imports, you're referring to something inside the package/file you're importing from. what you import can be a class, package or a file, each time you put a dot you ask something that is inside the instance before it.

parent/
    __init__.py
    file.py
    one/
        __init__.py
        anotherfile.py
    two/
        __init__.py
    three/
        __init__.py

for example you have this, when you pass import parent.file you're actually importing another python module that may contain classes and variables, so to refer to a specific variable or class inside that file you do from parent.file import class for example.

this may go further, import a packaging inside another package or a class inside a file inside a package etc (like import parent.one.anotherfile) For more info read Python documentation about this.