Python | Extend tuples by count of elements in tuple

Sometimes, while working with data, we can have an application in which we need to duplicate tuple elements by the amount of element count. This is very unique application but can occur in certain cases. Let's discuss certain ways in which this task can be performed. 

Method #1: Using nested loops This is the brute force method by which this task can be performed. In this, the outer loop is for iteration to each element in list and inner loop is to add the similar element equating to length of respective tuple by outer loop. 

# Python3 code to demonstrate working of
# Extend tuples by count in list
# using nested loop

# initialize list of tuple
test_list = [('1', '4', '6'), ('5', '8'), ('2', '9'), ('1', )]

# printing original tuples list
print("The original list : " + str(test_list))

# Extend tuples by count in list
# using nested loop
res = []
for sub in range(len(test_list)):
    for ele in range(len(test_list[sub])):
        res.append(test_list[sub])

# printing result
print("The modified and extended list is : " + str(res))

The original list : [('1', '4', '6'), ('5', '8'), ('2', '9'), ('1',)]
The modified and extended list is : [('1', '4', '6'), ('1', '4', '6'), ('1', '4', '6'), ('5', '8'), ('5', '8'), ('2', '9'), ('2', '9'), ('1',)]

Time complexity: O(n^2), where n is the total number of elements in the list of tuples.
Auxiliary space: O(n), where n is the total number of elements in the result list.

Method #2 : Using loop + chain() This is yet another way in which this task can be performed. In this, we reduce one loop, inner loop and multiply the tuples into one and flatten using chain(). It may have certain overheads depending upon different cases. 

# Python3 code to demonstrate working of
# Extend tuples by count in list
# using loop + chain()
from itertools import chain

# initialize list of tuple
test_list = [('1', '4', '6'), ('5', '8'), ('2', '9'), ('1', )]

# printing original tuples list
print("The original list : " + str(test_list))

# Extend tuples by count in list
# using loop + chain()
res = []
for sub in range(len(test_list)):
    res.append([test_list[sub]]*len(test_list[sub]))
res1 = chain(*res)
res = list(res1)

# printing result
print("The modified and extended list is : " + str(res))

The original list : [('1', '4', '6'), ('5', '8'), ('2', '9'), ('1',)]
The modified and extended list is : [('1', '4', '6'), ('1', '4', '6'), ('1', '4', '6'), ('5', '8'), ('5', '8'), ('2', '9'), ('2', '9'), ('1',)]

Time Complexity: O(n^2) where n is the length of the list "test_list".
Auxiliary Space: O(n^2) where n is the length of the list "test_list".

Method #3 : Using * operator and extend() method

# Python3 code to demonstrate working of
# Extend tuples by count in list

# initialize list of tuple
test_list = [('1', '4', '6'), ('5', '8'), ('2', '9'), ('1', )]

# printing original tuples list
print("The original list : " + str(test_list))

# Extend tuples by count in list
# using nested loop
res = []
for i in test_list:
    a = [i]*len(i)
    res.extend(a)
# printing result
print("The modified and extended list is : " + str(res))

The original list : [('1', '4', '6'), ('5', '8'), ('2', '9'), ('1',)]
The modified and extended list is : [('1', '4', '6'), ('1', '4', '6'), ('1', '4', '6'), ('5', '8'), ('5', '8'), ('2', '9'), ('2', '9'), ('1',)]

Time complexity: O(n^2), where n is the number of tuples in the list. The nested loop runs for each tuple in the list and for each element in the tuple.
Auxiliary space: O(n), where n is the number of tuples in the list.

Method #4 : Using list comprehension and * operator

# Python3 code to demonstrate working of
# Extend tuples by count in list
# using list comprehension and * operator

# initialize list of tuple
test_list = [('1', '4', '6'), ('5', '8'), ('2', '9'), ('1', )]

# printing original tuples list
print("The original list : " + str(test_list))

# Extend tuples by count in list
# using list comprehension and * operator
res = [i for i in test_list for _ in range(len(i))]

# printing result
print("The modified and extended list is : " + str(res))
#This code is contributed by Edula Vinay Kumar Reddy

The original list : [('1', '4', '6'), ('5', '8'), ('2', '9'), ('1',)]
The modified and extended list is : [('1', '4', '6'), ('1', '4', '6'), ('1', '4', '6'), ('5', '8'), ('5', '8'), ('2', '9'), ('2', '9'), ('1',)]

This method uses list comprehension to iterate through the original list and the * operator to repeat the tuple the number of times as the number of elements in the tuple. This method is more concise and more efficient than the previous methods as it only requires one pass over the original list and avoids unnecessary appending and extending. 
Time complexity: O(n), where n is the number of elements in the original list.
Auxiliary space: O(n)

Method #5: Using itertools.repeat() and itertools.chain.from_iterable()

1. The first step is to import the itertools module. This module provides various functions that operate on iterators to produce complex iterators.
2. The next step is to initialize a list of tuples called test_list. Each tuple contains some elements. This list will be used to demonstrate the operation of the itertools module.
3. After that, the original list of tuples is printed using the print() function.
4. The next step is to extend the tuples in the list by their length. This can be done using the itertools.repeat() function. It takes two arguments - the first argument is the object to be repeated, and the second argument is the number of times it should be repeated.
5. In this case, we want to repeat each tuple in test_list by its length. To do this, we can use a generator expression that iterates over each tuple in test_list and passes its length as the second argument to itertools.repeat(). This generator expression is passed to list() to convert it to a list.
6. The itertools.chain.from_iterable() function is then used to flatten the resulting list of repeated tuples into a single list. This function takes an iterable of iterables and returns a single iterable that concatenates all the inner iterables.
7. Finally, the modified and extended list is printed using the print() function.

import itertools

# initialize list of tuple
test_list = [('1', '4', '6'), ('5', '8'), ('2', '9'), ('1', )]

# printing original tuples list
print("The original list : " + str(test_list))

# Extend tuples by count in list
# using itertools.repeat() and itertools.chain.from_iterable()
res = list(itertools.chain.from_iterable(itertools.repeat(i, len(i)) for i in test_list))

# printing result
print("The modified and extended list is : " + str(res))

The original list : [('1', '4', '6'), ('5', '8'), ('2', '9'), ('1',)]
The modified and extended list is : [('1', '4', '6'), ('1', '4', '6'), ('1', '4', '6'), ('5', '8'), ('5', '8'), ('2', '9'), ('2', '9'), ('1',)]

The time complexity of this approach is O(nm), where n is the number of tuples and m is the maximum length of a tuple. 

The auxiliary space complexity is also O(nm), for the resulting list of extended tuples.

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