Importing in Python between three or more files not working

Question

Hello,

I hav codes eg1.py , eg2.py , eg3.py eg3.py imports eg2.py which in turn imports eg1.py

When i run eg3.py for first time everything is fine If i import it again and again only eg3.py runs

I need a solution for this.

I will code eg3.py in such a way that :

while(1):
    import eg2.py

Where I went wrong.Please give me a solution.

Answer 1

Huh? You can't loop an import, they are cached so it doesn't really do anything except waste cycles, after the first iteration.

How do you know that "only eg3.py" runs?

Answer 2

Do you want to execute the code in eg2.py when you import it? That is not a good solution. You should have a function containing your code in eg2.py and then execute this function in your while loop.

In eg2.py:

def my_func():
    # do useful stuff
    pass

In eg3.py

import eg2
while True:
    eg2.my_func()

Answer 3

If you import a module that is already imported, executable code in that module will not be re-run.

E.g.:

>>> import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!
>>> import this
>>>

Deleting the module from sys.modules will force a complete reload:

E.g.:

>>> import sys
>>> import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!
>>> del(sys.modules["this"])
>>> import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!
>>>

Edit: Also, what heikogerlach said: you're better off calling functions in the already imported modules than deleting/reloading them most of the time.