Given a tuple list, the following article focuses on how to convert it to a dictionary, with keys starting from a specified start value. This start value is only to give a head start, next keys will increment the value of their previous keys.
Input : test_list = [(4, 5), (1, 3), (9, 4), (8, 2), (10, 1)], start = 4
Output : {4: (4, 5), 5: (1, 3), 6: (9, 4), 7: (8, 2), 8: (10, 1)}
Explanation : Tuples indexed starting key count from 4.
Input : test_list = [(4, 5), (1, 3), (9, 4), (8, 2), (10, 1)], start = 6
Output : {6: (4, 5), 7: (1, 3), 8: (9, 4), 9: (8, 2), 10: (10, 1)}
Explanation : Tuples indexed starting key count from 6.
Method 1 : Using loop
In this, we construct the dictionary by iterating through each tuple and adding its position index, starting from start, as key-value pair in the dictionary.
Python3
# initializing listtest_list = [(4, 5), (1, 3), (9, 4), (8, 2), (10, 1)]# printing original listprint("The original list is : " + str(test_list))# initializing startstart = 4res = dict()for sub in test_list: # assigning positional index res[start] = sub start += 1# printing resultprint("Constructed dictionary : " + str(res)) |
The original list is : [(4, 5), (1, 3), (9, 4), (8, 2), (10, 1)]
Constructed dictionary : {4: (4, 5), 5: (1, 3), 6: (9, 4), 7: (8, 2), 8: (10, 1)}
Time Complexity: O(n)
Auxiliary Space: O(n)
Method 2 : Using dict() and enumerate()
In this, we convert tuple list to dictionary using dict(), and indexing is provided using enumerate().
Python3
# initializing listtest_list = [(4, 5), (1, 3), (9, 4), (8, 2), (10, 1)]# printing original listprint("The original list is : " + str(test_list))# initializing startstart = 4res = dict(enumerate(test_list, start=start))# printing resultprint("Constructed dictionary : " + str(res)) |
The original list is : [(4, 5), (1, 3), (9, 4), (8, 2), (10, 1)]
Constructed dictionary : {4: (4, 5), 5: (1, 3), 6: (9, 4), 7: (8, 2), 8: (10, 1)}
Time Complexity: O(n)
Auxiliary Space: O(n)
Using itertools.count to create an iterator for the keys:
test_list: a list of tuples
start: the starting index to use for the keys in the resulting dictionary
The function uses the zip function and the itertools.count function to create a dictionary where the keys start at start and increase by 1 for each tuple in test_list, and the values are the tuples themselves.
Python3
import itertoolsdef tuple_list_to_dict(test_list, start): res_dict = dict(zip(itertools.count(start), test_list)) return res_dict# Example usage 1test_list = [(4, 5), (1, 3), (9, 4), (8, 2), (10, 1)]start = 4result = tuple_list_to_dict(test_list, start)print(result) # Output : {4: (4, 5), 5: (1, 3), 6: (9, 4), 7: (8, 2), 8: (10, 1)}# Example usage 2test_list = [(4, 5), (1, 3), (9, 4), (8, 2), (10, 1)]start = 6result = tuple_list_to_dict(test_list, start)print(result) # Output : {6: (4, 5), 7: (1, 3), 8: (9, 4), 9: (8, 2), 10: (10, 1)} |
{4: (4, 5), 5: (1, 3), 6: (9, 4), 7: (8, 2), 8: (10, 1)}
{6: (4, 5), 7: (1, 3), 8: (9, 4), 9: (8, 2), 10: (10, 1)}
Time complexity: O(n)
Auxiliary Space: O(n)
Method 4: Using a list comprehension with zip()
Python3
# initializing listtest_list = [(4, 5), (1, 3), (9, 4), (8, 2), (10, 1)]# printing original listprint("The original list is: " + str(test_list))# initializing startstart = 4# using list comprehension with zip to create dictionaryres = {start+i: pair for i, pair in enumerate(test_list)}# printing resultprint("Constructed dictionary: " + str(res)) |
The original list is: [(4, 5), (1, 3), (9, 4), (8, 2), (10, 1)]
Constructed dictionary: {4: (4, 5), 5: (1, 3), 6: (9, 4), 7: (8, 2), 8: (10, 1)}
Time Complexity: O(n)
Auxiliary Space: O(n)
