Python: Using attributes with functions

Python offers the possibility to store attributes on a function. This can be very useful in a number of situations. Below an example that shows usage.

import inspect

def viewCount(page):
   #returns a function which keeps track of how many times the page got viewed
   def f():
       f.numberOfViews += 1
       return f.numberOfViews
   f.__name__ = "ViewCount for page " + page
   f.numberOfViews = 0 
   return f 
        
 
viewCountOne = viewCount('index.html')
viewCountTwo = viewCount('faq.html')
 
 
print viewCountOne()
print viewCountOne()
print viewCountTwo()
print viewCountOne()
print viewCountTwo()
print viewCountOne.__name__
print viewCountTwo.__name__

print hasattr(viewCountOne, 'numberOfViews')
print inspect.isfunction(viewCountOne)
print viewCountOne.__name__.find('index') != -1

1
2
1
3
2
ViewCount for page index.html
ViewCount for page faq.html
True
True
True