Python – Convert String List to Key-Value List dictionary

Given a string, convert it to key-value list dictionary, with key as 1st word and rest words as value list.

Input : test_list = [“gfg is best for geeks”, “CS is best subject”] Output : {‘gfg’: [‘is’, ‘best’, ‘for’, ‘geeks’], ‘CS’: [‘is’, ‘best’, ‘subject’]} Explanation : 1st elements are paired with respective rest of words as list. Input : test_list = [“gfg is best for geeks”] Output : {‘gfg’: [‘is’, ‘best’, ‘for’, ‘geeks’]} Explanation : 1st elements are paired with respective rest of words as list.

Method #1 : Using split() + loop

In this, we iterate for each string, and then perform split of string using split(), assign 1st element as key and pack other elements into list, using * operator and create key-value list pair.

Python3

# Python3 code to demonstrate working of
# Convert String List to Key-Value List dictionary
# Using split() + loop

# initializing list
test_list = ["gfg is best for geeks", "I love gfg", "CS is best subject"]

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


res = dict()
for sub in test_list:

    # split() for key
    # packing value list
    key, *val = sub.split()
    res[key] = val

# printing results
print("The key values List dictionary : " + str(res))

Output

The original list : ['gfg is best for geeks', 'I love gfg', 'CS is best subject']
The key values List dictionary : {'gfg': ['is', 'best', 'for', 'geeks'], 'I': ['love', 'gfg'], 'CS': ['is', 'best', 'subject']}

Time Complexity: O(n²) -> (loop +split)

Space Complexity: O(n)

Method #2 : Using split() + dictionary comprehension

This is similar way to solve this problem. In this, dictionary comprehension is used to solve this problem.

Python3

# Python3 code to demonstrate working of
# Convert String List to Key-Value List dictionary
# Using split() + dictionary comprehension

# initializing list
test_list = ["gfg is best for geeks", "I love gfg", "CS is best subject"]

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

# using dictionary comprehension to solve this problem
res = {sub[0] : sub[1:] for sub in (ele.split() for ele in test_list)}

# printing results
print("The key values List dictionary : " + str(res))

Output

The original list : ['gfg is best for geeks', 'I love gfg', 'CS is best subject']
The key values List dictionary : {'gfg': ['is', 'best', 'for', 'geeks'], 'I': ['love', 'gfg'], 'CS': ['is', 'best', 'subject']}

Time Complexity: O(n²)

Space Complexity: O(n)