Python – Add list elements to tuples list

Sometimes, while working with Python tuples, we can have a problem in which we need to add all the elements of a particular list to all tuples of a list. This kind of problem can come in domains such as web development and day-day programming. Let’s discuss certain ways in which this task can be done.

Input : test_list = [(5, 6), (2, 4), (5, 7), (2, 5)], sub_list = [5, 4] 
Output : [(5, 6, 5, 4), (2, 4, 5, 4), (5, 7, 5, 4), (2, 5, 5, 4)]

Input : test_list = [(5, 6), (2, 4), (5, 7), (2, 5)], sub_list = [5] 
Output : [(5, 6, 5), (2, 4, 5), (5, 7, 5), (2, 5, 5)] 

Method #1 : Using list comprehension + “+” operator
The combination of above functionalities can be used to solve this problem. In this, we perform task of adding tuple to list using “+” operator and iteration over all tuples is done using list comprehension.

Python3

# Python3 code to demonstrate working of
# Add list elements to tuples list
# Using list comprehension + "+" operator

# initializing list
test_list = [(5, 6), (2, 4), (5, 7), (2, 5)]

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

# initializing list
sub_list = [7, 2, 4, 6]

# Add list elements to tuples list
# Using list comprehension + "+" operator
res = [sub + tuple(sub_list) for sub in test_list]

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

Output : 

The original list is : [(5, 6), (2, 4), (5, 7), (2, 5)]
The modified list : [(5, 6, 7, 2, 4, 6), (2, 4, 7, 2, 4, 6), (5, 7, 7, 2, 4, 6), (2, 5, 7, 2, 4, 6)]

Time complexity: O(n), where n is the length of the input list test_list.
Auxiliary space: O(n), as it creates a new list res of the same length as the input list test_list. Additionally, it also creates a new list sub_list of length m (the length of the input list sub_list), but this is not dependent on the size of the input and is therefore considered constant space.

Method #2 : Using list comprehension + “*” operator
The combination of above functions can be used to solve this problem. In this, we perform the task of adding list to a tuple using pack-unpack operator “*”. This is more efficient method than above method.

Python3

# Python3 code to demonstrate working of
# Add list elements to tuples list
# Using list comprehension + "*" operator

# initializing list
test_list = [(5, 6), (2, 4), (5, 7), (2, 5)]

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

# initializing list
sub_list = [7, 2, 4, 6]

# Add list elements to tuples list
# Using list comprehension + "*" operator
res = [(*sub, *sub_list) for sub in test_list]

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

Output : 

The original list is : [(5, 6), (2, 4), (5, 7), (2, 5)]
The modified list : [(5, 6, 7, 2, 4, 6), (2, 4, 7, 2, 4, 6), (5, 7, 7, 2, 4, 6), (2, 5, 7, 2, 4, 6)]

Time complexity: O(n), where n is the length of the input list ‘test_list’. 
Auxiliary space: O(n), where n is the length of the input list ‘test_list’.

Method 3 : using a nested for loop.

• Initialize a list of tuples named test_list with elements (5, 6), (2, 4), (5, 7), (2, 5).
• Initialize a list named sub_list with elements 7, 2, 4, 6.
• Initialize an empty list named res.
• Start a for loop that iterates over each tuple in test_list.
• For each tuple in test_list, create a new empty tuple named new_tup.
• Start a nested for loop that iterates over each element in the current tuple.
• For each element in the current tuple, append it to new_tup.
• Start another nested for loop that iterates over each element in sub_list.
• For each element in sub_list, append it to new_tup.
• After all elements have been appended to new_tup, append the tuple to res.
• After all tuples in test_list have been processed, print the modified list by converting res to a string and concatenating it to a string “The modified list : “.
• End the program.
  

Python3

test_list = [(5, 6), (2, 4), (5, 7), (2, 5)]
sub_list = [7, 2, 4, 6]
res = []

# Loop through each tuple in the test_list
for tup in test_list:
    new_tup = ()
    # Loop through each element in the tuple and add it to the new tuple
    for ele in tup:
        new_tup += (ele,)
    # Add the sub_list to the new tuple
    for ele in sub_list:
        new_tup += (ele,)
    # Append the new tuple to the result list
    res.append(new_tup)

# Print the result
print("The modified list : " + str(res))

Output

The modified list : [(5, 6, 7, 2, 4, 6), (2, 4, 7, 2, 4, 6), (5, 7, 7, 2, 4, 6), (2, 5, 7, 2, 4, 6)]

The time complexity of this approach is O(n^2), where n is the length of the test_list. 

The auxiliary space complexity is O(n), as we need to store the modified tuples in a new list.

METHOD 4: Using map(), lambda function, and tuple concatenation

APPROACH:

This program takes a list of tuples as input and adds a new set of elements to each tuple. Then it returns the modified list of tuples as output.

ALGORITHM:

1. Define the original list of tuples.
2. Define the modified list as an empty list.
3. Iterate through each tuple in the original list.
4. Convert each tuple to a list.
5. Append the new set of elements to the list.
6. Convert the modified list back to a tuple.
7. Append the modified tuple to the modified list.
8. Return the modified list.

Python3

original_list = [(5, 6), (2, 4), (5, 7), (2, 5)]

modified_list = list(map(lambda x: tuple(list(x) + [7, 2, 4, 6]), original_list))

print("The modified list:", modified_list)

Output

The modified list: [(5, 6, 7, 2, 4, 6), (2, 4, 7, 2, 4, 6), (5, 7, 7, 2, 4, 6), (2, 5, 7, 2, 4, 6)]

Time complexity: O(n), where n is the length of the original list.
Space complexity: O(n), where n is the length of the original list.