 <p>A crude approach (while <em>guessing</em> what you're trying to do):</p> <pre><code>#!/usr/bin/env python import pprint revisions = [ ['01.02.2010','abc','qwe'], ['02.02.2010','abc','qwe'], ['03.02.2010','aaa','qwe'], ['04.02.2010','aaa','qwe'], ['05.02.2010','aaa','qwe'], ['06.02.2010','aaa','dsa'], ] uniq, seen = [], set() # sets have O(1) membership tests for rev in revisions: if tuple(rev[1:]) in seen: continue else: seen.add(tuple(rev[1:])) uniq.append(rev) pprint.pprint(uniq) # prints: # [['01.02.2010', 'abc', 'qwe'], # ['03.02.2010', 'aaa', 'qwe'], # ['06.02.2010', 'aaa', 'dsa']] </code></pre>