Generating all combinations taking one element from each list in Python can be done easily using itertools.product function. Combinations without itertools or recursion I'm attempting to create a function that will take a list of items and a number of combinations and return those unique combinations without repetition. Two such features I’ve discovered recently are the permutations and combinations functions of Python’s itertools module. In the course of solving certain math problems, I found it useful to write a function, combinations_by_subset, that yields these combinations sorted by subset order (for lack of a better name). I'm also trying to achieve this without using itertools.combinations() or recursion. Maybe you want to change the API slightly — say, returning a list instead of an iterator, or you might want to operate on a NumPy array. from itertools import combinations for i in combinations(L,2): print(i) gives ... Python combinations without repetitions; Get unique combinations of elements from a python list [duplicate] itertools.combinations(iterable, r) To find all combinations of size 2, a solution is to use the python module called itertools. Python without using itertools. Combinations in Python without using itertools Itertools in Python is a module that produces complex iterators with the help of methods that work on iterators. Below is an example that shows how to use the itertools.combinations() function:-import itertools permutation in python without itertools python permutations binary string generator python generate binary permutations create binary combinations python Python – Itertools.Permutations Itertool is a module provided by Python for creating iterators for efficient looping. This module works as a fast, memory-efficient tool that is used either by themselves or in combination to form iterator algebra. 3 VIEWS. Python combination without repetition with sublist's items; combination without repetition python Code Example; ... (itertools.combinations(t, 4)) would do a fine job for most cases, but it still iterates all repetitive combinations internally and so it can be computationally heavy. In this article , I will explain each function starting with a basic definition and a standard application of the function using a python code snippet and its output. Under the hood, Python uses a C implementation of the combinations algorithm. The chain and combinations functions of itertools work well, but you need to use Python 2.6 or greater: import itertools def all_combinations(any_list): return itertools.chain.from_iterable( itertools.combinations(any_list, i + 1) for i in xrange(len(any_list))) You can then call this as such: It is a part of itertools module ... combination = [p for p in itertools.product(*list)] At this point, we can print combinations and take a look at the combinations that has been generated. To get all possible combinations of a list’s elements you can use itertools.combinations function below is the code for the same: itertools.combinations(iterable, r) This function will return r length subsequences of elements from the input iterable. In Python, itertools.combinations yields combinations of elements in a sequence sorted by lexicographical order. Once in a while, you might want to generate combinations without using itertools. For example, to list all 3-length combinations of the string 'abcde': Combinations without itertools. The Python Itertools module is a standard library module provided by Python 3 Library that provide various functions to work on iterators to create fast , efficient and complex iterations.. 0. manojnayakkuna 1. GitHub Gist: instantly share code, notes, and snippets. Last Edit: 17 hours ago. Python: All Possible Combinations.