I'm pretty new to Python and am getting a little confused as to what you can and can't do with lists. I have two lists that I want to compare and return matching and nonmatching elements in a binary format. List1 is of constant length, while the length of List2 differs (but is always shorter than List1).

For example:

List1 = ['dog', 'cat', 'pig', 'donkey']
List2 = ['dog', 'cat', 'donkey']

Output wanted:

List3 = [1, 1, 0, 1]

The code I have so far is:

def match_nonmatch(List1, List2):List3 = []for i in range(len(List1)):for j in range(len(List2)):if List1[i] == List2[j]:List3.append(1)else:List3.append(0)return List3

I am able to return the matches when I compare the lists, but when I include the else statement shown above to return the nonmatches I end up with a list that is way longer than it should be. For instance, when I use a list comparing 60 items, I get a list that contains 3600 items rather than 60.

I'd appreciate it if someone could explain to me the problem with my code as it currently stands and suggest how I could modify the code so it does what I want.

Use set instead of list. This way you can do lots of nice things:

set1 = set(['dog', 'cat', 'pig', 'donkey'])
set2 = set(['dog', 'cat', 'donkey'])matched = set1.intersection(set2) # set(['dog', 'cat', 'donkey'])
unmatched = set1.symmetric_difference(set2) # set(['pig'])

I know it's not exactly what you asked for, but it's usually a better practice to use sets instead of lists when doing this sort of things.

More on sets here: http://docs.python.org/library/stdtypes.html#set