How to make combination of numbers in python

1. Use the itertools.combinations[] Function to Find the Combinations of a List in Python
2. Use the itertools.combinations_with_replacement[] Function to Find the Combinations of a List in Python
3. Create a User-Defined powerset[] Function to Find the Combinations of a List in Python

A combination is a technique that determines the number of possible arrangements in a collection of elements. In a combination of elements, the elements are selected in an arbitrary order.

In this tutorial, we will find the total combinations of a list’s elements in Python.

The function combinations[list_name, x] from the itertools module takes the list name and a number x as the parameters and returns a list of tuples each of length x containing all the possible combinations of one element in the list with the other elements.

For example,

from itertools import combinations
A = [10, 5, 'Hi']
temp = combinations[A, 2]
for i in list[temp]:
	print [i]

Output:

[10, 5]
[10, 'Hi']
[5, 'Hi']

A sorted list will output the combination tuples in sorted order. A combination of one element in the list with itself is not possible using the combinations[] function.

The function combinations_with_replacement[list_name, x] from the itertools module takes the list name and a number ‘x’ as the parameters and returns a list of tuples each of length ‘x’ containing all possible combinations of the list’s elements. A combination of one element in the list with itself is possible using this function.

For example,

from itertools import combinations_with_replacement
A = [1, 5, 'Hi']
temp = combinations_with_replacement[A, 2]
for i in list[temp]:
	print [i]

Output:

[1, 1]
[1, 5]
[1, 'Hi']
[5, 5]
[5, 'Hi']
['Hi', 'Hi']

Create a User-Defined powerset[] Function to Find the Combinations of a List in Python

In mathematics, a power set of any set is a set which contains all the possible subsets of a given set along with an empty set. Power set of set S = {2, 5, 10} is {{}, {2}, {5}, {10}, {2, 5}, {2, 10}, {5, 10}, {2, 5, 10}}. The following function powerset[] is used to loop through all the lengths ‘r’ of the list and print all the possible combinations of the list’s elements.

For example,

from itertools import chain, combinations
def powerset[list_name]:
    s = list[list_name]
    return chain.from_iterable[combinations[s, r] for r in range[len[s]+1]]

A = [60, 7, 'Hi']
for x in powerset[A]:
    print[x]

Output:

[]
[1,]
[5,]
['Hi',]
[1, 5]
[1, 'Hi']
[5, 'Hi']
[1, 5, 'Hi']

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