I'm trying to generate the morris sequence in python. My current solution is below, but I feel like I just wrote c in python. Can anyone provide a more pythonic solution? def morris(x): a = ['1', '11'] yield a[0] yield a[1] while len(a) <= x: s = '' count = 1 al = a[-1] for i in range(0,le...
I have a list of items (which are HTML table rows, extracted with Beautiful Soup) and I need to iterate over the list and get even and odd elements (I mean index) for each loop run. My code looks like this: for top, bottom in izip(table[::2], table[1::2]): #do something with top #do something else with bottom How to make this...
in my views, if i import an itertools module: from itertools import chain and i chain some objects with it: franktags = Frank.objects.order_by('date_added').reverse().filter(topic__exact='art') amytags = Amy.objects.order_by('date_added').reverse().filter(topic__exact='art') timtags = Tim.objects.order_by('date_added').reverse().fi...
in my django view, if i import operator, and use the following code: multitags = sorted(multitags, key=operator.attrgetter('date_added')) is there an easy way to reverse the order – such that i get the dates in descending order (today at top; last week underneath)? ...
if my views code is: arttags = sorted(arttags, key=operator.attrgetter('date_added'), reverse=True) what is the argument that will limit the result to 50 tags? I'm assuming this: .... limit=50) is incorrect. more complete code follows: videoarttags = Media.objects.order_by('date_added'),filter(topic__exact='art') audioarttags =...
Question ago (http://stackoverflow.com/questions/1271320/reseting-generator-object-in-python) I was recommended to use itertools.tee. Actually I'm using IronPython, in the library we can see many usage of this feature, but there is no implementation (in *.py). That is why I'm confusing how to include this package to my c# project? ...
I'm searching for a library (preferably generic) that generates iterable combinations and permutations of data contained in collections. Cartesian product would also be nice. The best way of describing what I want would be "itertools for Java". ...
I have 2 dimensional list created at runtime (the number of entries in either dimension is unknown). For example: long_list = [ [2, 3, 6], [3, 7, 9] ] I want to iterate through it by getting the ith entry from each list inside the long_list: for entry in long_list.iter(): #entry will be [2, 3] then [3, 7] then [6, 9] I know tha...
Original question: Can someone tell me how to use "slice lists" and the "ellipsis"? When are they useful? Thanks. Here's what the language definition says about "slice_list" and "ellipsis"; Alex Martelli's answer points out their origin, which is not what I had envisioned. [http://docs.python.org/reference/expressions.html#tok-slici...
I have a list of lists (generated with a simple list comprehension): >>> base_lists = [[a, b] for a in range(1, 3) for b in range(1, 6)] >>> base_lists [[1,1],[1,2],[1,3],[1,4],[1,5],[2,1],[2,2],[2,3],[2,4],[2,5]] I want to turn this entire list into a tuple containing all of the values in the lists, i.e.: resulting_tuple = (1,1,1,2...
I want to get started trying to develop a few simple applications with PyObjC. I installed PyObjC and the Xcode templates. I know that PyObjC itself works, since I've run this script successfully. When I tried to create a project from the Cocoa-Python Application template and ran it, I got this error: Traceback (most recent call last): ...
I'm trying to create a possible list of codons given a protein sequence. Basically, the script i'm trying to create will process a given string input and outputs a possible combinations of another set of strings the input represents. For example, the character 'F' represents either 'UUU' or 'UUC'; the character 'I' represents either 'A...
I'm looking for a way to "page through" a Python iterator. That is, I would like to wrap a given iterator iter and page_size with another iterator that would would return the items from iter as a series of "pages". Each page would itself be an iterator with up to page_size iterations. I looked through itertools and the closest thing ...
Python's itertools module provides a lots of goodies with respect to processing an iterable/iterator by use of generators. For example, permutations(range(3)) --> 012 021 102 120 201 210 combinations('ABCD', 2) --> AB AC AD BC BD CD [list(g) for k, g in groupby('AAAABBBCCD')] --> AAAA BBB CC D What are the equivalent in Ruby? By eq...
I have a list of strings similar to this list: tags = ('apples', 'apricots', 'oranges', 'pears', 'peaches') How should I go about grouping this list by the first character in each string using itertools.groupby()? How should I supply the 'key' argument required by itertools.groupby()? ...
In python I have the following function: def is_a_nice_element(element, parameter): #do something return True or False Now I would like to filter a list with this function as predicate, giving a fixed parameter. Python has the itertools.ifilter function, but I can't figure out how to pass the parameter. Is this possible? If no...
I want to group by on dict key >>> x [{'a': 10, 'b': 90}, {'a': 20}, {'a': 30}, {'a': 10}] >>> [(name, list(group)) for name, group in groupby(x, lambda p:p['a'])] [(10, [{'a': 10, 'b': 90}]), (20, [{'a': 20}]), (30, [{'a': 30}]), (10, [{'a': 10}])] This must group on key 10 :( ...
Hi everyone, I have the following input: input = [(dog, dog, cat, mouse), (cat, ruby, python, mouse)] and trying to have the following output: outputlist = [[0, 0, 1, 2], [1, 3, 4, 2]] outputmapping = {0:dog, 1:cat, 2:mouse, 3:ruby, 4:python, 5:mouse} Any tips on how to handle given with scalability in mind (var input can get rea...
I have a list which contains a number of things: lista = ['a', 'b', 'foo', 'c', 'd', 'e', 'bar'] I'd like to get the first item in the list that fulfils a predicate, say len(item) > 2. Is there a neater way to do it than itertools' dropwhile and next? first = next(itertools.dropwhile(lambda x: len(x) <= 2, lista)) I did use [item f...
I have a set of trajectories, made up of points along the trajectory, and with the coordinates associated with each point. I store these in a 3d array ( trajectory, point, param). I want to find the set of r trajectories that have the maximum accumulated distance between the possible pairwise combinations of these trajectories. My first ...