[ Python 常見問題 ] How to import a module given the full path?

Source From Here 
Question 
How can I load a Python module given its full path? Note that the file can be anywhere in the filesystem, as it is a configuration option. 

How-To 
Consider you have a python module under C:/tmp/test.py: 

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1. def add(x, y):  
2.     return x + y  
3.   
4. class Add:  
5.     def __init__(self, x):  
6.         self.x = x;  
7.   
8.     def __call__(self, y):  
9.         return self.x + y  

For Python 3.5+ use importlib: 

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1. In [1]: import importlib.util  
2.   
3. In [2]: spec = importlib.util.spec_from_file_location('test.add', "C:/tmp/test.py")  
4.   
5. In [3]: spec.__class__  
6. Out[3]: _frozen_importlib.ModuleSpec  
7.   
8. In [4]: foo = importlib.util.module_from_spec(spec)  
9.   
10. In [5]: foo.__class__  
11. Out[5]: module  
12.   
13. In [7]: spec.loader.exec_module(foo)  
14.   
15. In [8]: foo.add(1, 2)  
16. Out[8]: 3  
17.   
18. In [10]: a = foo.Add(2)  
19. In [12]: a(3)  
20. Out[12]: 5  

For Python 3.3 and 3.4 use: 

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1. from importlib.machinery import SourceFileLoader  
2.   
3. foo = SourceFileLoader('test.add', "C:/tmp/test.py").load_module()  
4. foo.add(1, 2)  # Output 3  

Python 2 use: 

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1. import imp  
2.   
3. foo = imp.load_source('test.add', "C:/tmp/test.py")  
4. foo.add(1, 2)  # Output 3  

There are equivalent convenience functions for compiled Python files and DLLs. 

See also. http://bugs.python.org/issue21436. 

Supplement 
* FAQ - How to import other Python files?