How To Compare Items In Two Lists Python 3.3
Question: I tried using `cmp(list1, list2)` to learn it's no longer supported in Python
3.3. I've tried many other complex approaches, but none have worked.

I have two lists of which both contain just words and I want it to check to
see how many words feature in both and return the number for how many.


Answer: You can find the length of the set intersection using `&` like this:

    
    
    len(set(list1) & set(list2))
    

**Example:**

    
    
    >>>len(set(['cat','dog','pup']) & set(['rat','cat','wolf']))
    1
    >>>set(['cat','dog','pup']) & set(['rat','cat','wolf'])
    {'cat'}
    

Alternatively, if you don't want to use sets for some reason, you can always
use
[`collections.Counter`](https://docs.python.org/dev/library/collections.html#collections.Counter),
which supports most multiset operations:

    
    
    >>> from collections import Counter 
    >>> print(list((Counter(['cat','dog','wolf']) & Counter(['pig','fish','cat'])).elements()))
    ['cat']
    

