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I am using python 3.4.4 and testing "init.py" feature by creating a sample package But unable to implement. The mentioned case is working perfectly in case of python 2.7.13 version. Can anyone tell me the mistake i am doing or is there any change in syntax of python 3.x versions. Please help me to learn Python 3?

Dir Structure:

TestPackage/
    __init__.py
    TestModule.py
run.py

Content of TestModule.py :

def TestFun():
    print("Welcome")

Content of __init__.py :

from TestModule import TestFun

Content of run.py :

from TestPackage import TestFun
TestFun()

When i execute run.py file, i got the following error:

Traceback (most recent call last):
  File "D:\CASE03\run01.py", line 1, in <module>
    from TestPackage import TestFun
  File "D:\CASE03\TestPackage\__init__.py", line 1, in <module>
    from TestModule import TestFun
ImportError: No module named 'TestModule'

But when i use python 2.7.13 it works perfectly fine. Please guide me.

Inside of __init__.py, if you change

from TestModule import TestFun

to

from .TestModule import TestFun

You'll get the expected behavior.

See: PEP 328 (sections regarding relative imports using leading dots).

Importing, Importing¶. Python 3 brings a complete overhaul of the way import works – the import machinery was ported from C to Python. Developer-visible changes are  The import system¶ Python code in one module gains access to the code in another module by the process of importing it. The import statement is the most common way of invoking the import machinery, but it is not the only way. Functions such as importlib.import_module() and built-in __import__() can also be used to invoke the import machinery.

Try changing the __init__.py to the below code:

from TestPak.TestModule import TestFun

5. The import system, path for a top level package) changes. With namespace packages, there is no parent/__init__.py file. In fact, there may be multiple parent  import_module() from importlib is very important if you want to import any kind of modules dynamically, simply by passing a string value. After you have gotten the imported module as an object, you can use getattr() function, passing in the module object, and a string value of a class/variable/function you want.

The simplest solution is to set __init__.py as a blank file. In case you are interested in controlling what gets imported from your module when you do from Testmodule import *, you can include __all__ = ['TestFun'] in __init__.py file.

Absolute vs Relative Imports in Python – Real Python, Implicit relative imports have been deprecated in Python 3, so I won't be covering particularly for shared projects where directory structure is likely to change. A relative import is when you import from a module relative to that module's location, instead of absolutely from sys.path. As for import *, Python 2 allowed star imports within functions, for instance: >>> def f(): from math import * print sqrt A warning is issued for this in Python 2 (at least recent versions).

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Installing, Importing, and Aliasing Modules in Python 3, Dynamic Import in Python 3. Last updated Feb 10, 2018 This time, I'm going to change the import a bit, like so: import sys import inspect import pkgutil from  Import in python is similar to #include header_file in C/C++. Python modules can get access to code from another module by importing the file/function using import. The import statement is the most common way of invoking the import machinery, but it is not the only way.

Dynamic Import in Python 3, Local application/library specific imports. It is also good to order import statements alphabetically within each import group. filter_none. edit Python 3 Tkinter; New python 3 modules; Blender and Python 3.1 are fighting! urllib in python 3.1; TKInter and Python 3.2; Python 3.2.2 Problem; PIL or equivalent for saving images in Python 3.x; Python 3.2.1 was released on July 10th, 2011. Python Program not running correctly in python 3.2 commnad line; PEP 8 installtion with python 3.2

Comments
  • It is (a change in Python3). (Here's another answer regarding the change)
  • While this will work, it will couple the contents of the init file with the package name (which may change). Not a huge deal, but the relative import (leading dot) exists and seems cleaner.