Suppose there are two lists: l1 = [2,2,3] l2 = ['a','b','c'] I wonder how one finds the product of the two such that the output would be: #output: ['a','a','b','b','c','c','c'] if I do: l3 = [] f...

I have a list of size < N and I want to pad it up to the size N with a value. Certainly, I can use something like the following, but I feel that there should be something I missed: >>&gt...

I want to do permutation in Perl. For example I have three arrays: ["big", "tiny", "small"] and then I have ["red", "yellow", "green"] and also ["apple", "pear", "banana"]. How do I get: ["big", ...

What's the most Pythonic efficient way to iterate over a list in sliding pairs? Here's a related example: >>> l ['a', 'b', 'c', 'd', 'e', 'f', 'g'] >>> for x, y in itertools.izip...

I have two lists: big_list = [2, 1, 2, 3, 1, 2, 4] sub_list = [1, 2] I want to remove all sub_list occurrences in big_list. result should be [2, 3, 4] For strings you could use this: '2123124...

So suppose we want to produce the list [0, 1, -1, 2, -2, ...in Haskell. What is the most elegant way of accomplishing this? I came up with this solution: solution = [0] ++ foldr (\(a,b) c->a:...

I have a list structure which represents a table being handed to me like this > l = list(list(1, 4), list(2, 5), list(3, 6)) > str(l) List of 3 $ :List of 2 ..$ : num 1 ..$ : num 4 $ :Li...

In Python, the only way I can find to concatenate two lists is list.extend, which modifies the first list. Is there any concatenation function that returns its result without modifying its ar...

In other languages (ruby, python, ...) I can use zip(list1, list2) which works like this: If list1 is {1,2,3,4} and list2 is {a,b,c} then zip(list1, list2) would return: {(1,a), (2,b), (3,c), (d,...

I'm trying to implement Ravi Sethi's Little Quilt language in Haskell. An overview of Sethi's little quilt can be seen here: http://poj.org/problem?id=3201 Here are the functions that I have so fa...

Is there a python builtin that does the same as tupler for a set of lists, or something similar: def tupler(arg1, *args): length = min([len(arg1)]+[len(x) for x in args]) out = [] for i in rang...

[3, 3, 3, 4, 4, 2] Would be: [ (3, 3), (4, 2), (2, 1) ] The output should be sorted by highest count first to lowest count. In this case, 3 to 2 to 1.

As part of a bigger problem of enumerating a set, I need to write an OCaml function 'choose' which takes a list and outputs as the list of all possible sequences of size k made up of elements of th...

I know that the map function takes each element of a list (a sequence) and applies a function to it. Recursively (and without respect to termination conditions, etc) map(s, f) = f(s.head) :: map(...