http://code.activestate.com/recipes/tags/itertools-generator/2012-04-16T13:08:55-07:00ActiveState Code Recipes2012-04-03T17:13:35-07:00Garretthttp://code.activestate.com/recipes/users/4181290/http://code.activestate.com/recipes/578092-flattening-an-arbitrarily-deep-list-or-any-iterato/

<p style="color: grey"> Python recipe 578092 by <a href="/recipes/users/4181290/">Garrett</a> (<a href="/recipes/tags/flatten/">flatten</a>, <a href="/recipes/tags/iterator/">iterator</a>, <a href="/recipes/tags/itertools/">itertools</a>, <a href="/recipes/tags/list/">list</a>, <a href="/recipes/tags/python/">python</a>, <a href="/recipes/tags/tuple/">tuple</a>). Revision 6. </p> <p>What if you had a list like this: [1, -10, [1,2,[3,4]], xrange(200)], and you just wanted to go through each element in order (wanted it to return a simple list of [1,-10,1,2,3,4,1,2,3,4...199])</p> <p>I've seen a couple of attempts to flatten arbitrarily deep lists. Many of them involve recursion, like this one: <a href="http://rightfootin.blogspot.com/2006/09/more-on-python-flatten.html" rel="nofollow">http://rightfootin.blogspot.com/2006/09/more-on-python-flatten.html</a></p> <p>Recursion is generally considered non-pythonic (at least to my knowledge), so I have used one which just involves simple iterators instead. Also, recursion will fail if the list is too deep (so it wouldn't really be arbitrary, would it?).</p>

2012-04-16T13:08:55-07:00Josh Bodehttp://code.activestate.com/recipes/users/4179046/http://code.activestate.com/recipes/577852-iterator-offsetter/

<p style="color: grey"> Python recipe 577852 by <a href="/recipes/users/4179046/">Josh Bode</a> (<a href="/recipes/tags/iterable/">iterable</a>, <a href="/recipes/tags/itertools/">itertools</a>, <a href="/recipes/tags/offset/">offset</a>). Revision 2. </p> <p>Produces a list of copies of an iterable that are offset by the supplied offsets.</p>

2011-06-23T16:36:38-07:00Andrew Dalkehttp://code.activestate.com/recipes/users/912777/http://code.activestate.com/recipes/577768-lazy-ordered-unique-elements-from-an-iterator/

<p style="color: grey"> Python recipe 577768 by <a href="/recipes/users/912777/">Andrew Dalke</a> (<a href="/recipes/tags/iterator/">iterator</a>, <a href="/recipes/tags/itertools/">itertools</a>, <a href="/recipes/tags/unique/">unique</a>). Revision 2. </p> <p>This implements a "unique" filter. Its input is an iterator of hashable items. It returns an iterator containing only the unique items of the input, in input order. That is, list(unique("cabbage")) produces ["c", "a", "b", "g"]. The implementation is lazy. The function supports the "key" parameter, which provides an alternate form of comparison.</p> <p>(Note: a better version of this is available from the itertools documentation as unique_everseen )</p>

2010-07-19T13:53:41-07:00Daniel Cohnhttp://code.activestate.com/recipes/users/4172918/http://code.activestate.com/recipes/577309-yet-another-roundrobin/

<p style="color: grey"> Python recipe 577309 by <a href="/recipes/users/4172918/">Daniel Cohn</a> (<a href="/recipes/tags/collections/">collections</a>, <a href="/recipes/tags/itertools/">itertools</a>, <a href="/recipes/tags/roundrobin/">roundrobin</a>). Revision 2. </p> <p>This recipe provides a decently simple implementation of a roundrobin using itertools and deque.</p>