How to prevent a module from being imported twice?
import, module, python
Solution
Python modules aren't imported multiple times. Just running import two times will not reload the module. If you want it to be reloaded, you have to use the `reload` statement. Here's a demo
`foo.py` is a module with the single line
print("I am being imported")
And here is a screen transcript of multiple import attempts.
>>> import foo
Hello, I am being imported
>>> import foo # Will not print the statement
>>> reload(foo) # Will print it again
Hello, I am being imported
Problem
When writing python modules, is there a way to prevent it being imported twice by the client codes? Just like the c/c++ header files do: ``` #ifndef XXX #define XXX ... #endif ``` Thanks very much!