Sometimes, while working with Python strings, we can have problems in which we need to convert a string’s key-value pairs to the dictionary. This can have applications in which we are working with string data that needs to be converted. Let’s discuss certain ways in which this task can be performed.
Method #1 : Using map() + split() + loop
The combination of above functionalities can be used to perform this task. In this, we perform the conversion of key-value pairs to the dictionary using a map, and splitting key-value pairs is done using split().
Python3
# Python3 code to demonstrate working of# Convert key-value String to dictionary# Using map() + split() + loop# initializing stringtest_str = 'gfg:1, is:2, best:3'# printing original stringprint("The original string is : " + str(test_str))# Convert key-value String to dictionary# Using map() + split() + loopres = []for sub in test_str.split(', '): if ':' in sub: res.append(map(str.strip, sub.split(':', 1)))res = dict(res)# printing resultprint("The converted dictionary is : " + str(res)) |
The original string is : gfg:1, is:2, best:3
The converted dictionary is : {'gfg': '1', 'is': '2', 'best': '3'}
Time complexity: O(n), where n is the length of the input string.
Auxiliary space: O(n), where n is the length of the input string.
Method #2 : Using dict() + generator expression + split() + map()
This is yet another way in which this problem can be solved. In this, we perform the task in a similar way as above but in 1 liner way using dict() and generator expression.
Python3
# Python3 code to demonstrate working of# Convert key-value String to dictionary# Using dict() + generator expression + split() + map()# initializing stringtest_str = 'gfg:1, is:2, best:3'# printing original stringprint("The original string is : " + str(test_str))# Convert key-value String to dictionary# Using dict() + generator expression + split() + map()res = dict(map(str.strip, sub.split(':', 1)) for sub in test_str.split(', ') if ':' in sub)# printing resultprint("The converted dictionary is : " + str(res)) |
The original string is : gfg:1, is:2, best:3
The converted dictionary is : {'gfg': '1', 'is': '2', 'best': '3'}
The Time and Space Complexity for all the methods are the same:
Time Complexity: O(n)
Auxiliary Space: O(n)
Method #3: Using dict comprehension + split()
This is yet another way in which this problem can be solved. In this, we perform the task in a similar way as above but in 1 liner way using dict comprehension and split().
Python
# Python3 code to demonstrate working of# Convert key-value String to dictionary# Using dict comprehension + split()# initializing stringtest_str = 'gfg:1, is:2, best:3'# printing original stringprint("The original string is : " + str(test_str))# Convert key-value String to dictionary# Using map() + split() + loopres = test_str.split(', ')res = {i.split(':')[0]: i.split(':')[1] for i in res}# printing resultprint("The converted dictionary is : " + str(res)) |
The original string is : gfg:1, is:2, best:3
The converted dictionary is : {'is': '2', 'gfg': '1', 'best': '3'}
Method 4 : using regular expressions
Step-by-step explanation:
- Define a regular expression pattern that matches each key-value pair: (\w+):(\d+)
(\w+): match one or more word characters (letters, digits, or underscores), captured as a group
:: match a colon
(\d+): match one or more digits, captured as a group - Use re.findall() to find all non-overlapping matches of the pattern in the input string.
- Use dict() to convert the list of matches into a dictionary.
Python3
import re# initializing stringtest_str = 'gfg:1, is:2, best:3'# printing original stringprint("The original string is : " + str(test_str))# Convert key-value String to dictionary# Using regular expressionspattern = r'(\w+):(\d+)'res = dict(re.findall(pattern, test_str))# printing resultprint("The converted dictionary is : " + str(res)) |
The original string is : gfg:1, is:2, best:3
The converted dictionary is : {'gfg': '1', 'is': '2', 'best': '3'}
Time complexity: O(n), where n is the length of the input string.
Auxiliary space complexity is O(n + k).
