Convert key-value pair comma separated string into dictionary - Python

In Python, we might have a string containing key-value pairs separated by commas, where the key and value are separated by a colon (e.g., "a:1,b:2,c:3"). The task is to convert this string into a dictionary where each key-value pair is represented properly. Let's explore different ways to achieve this.

Using Dictionary Comprehension with split

This method uses dictionary comprehension to split the string and create a dictionary.

# Input string
s = "a:1,b:2,c:3"

# Converting to dictionary using dictionary comprehension
d = {k: int(v) for k, v in (item.split(":") for item in s.split(","))}

print(d)

{'a': 1, 'b': 2, 'c': 3}

Explanation:

• The string is split by commas to get individual key-value pairs.
• Each pair is further split by a colon to separate the key and value.
• Dictionary comprehension creates a dictionary with the key and integer-converted value.

Let's explore some more ways and see how we can convert key-value pair comma separated string into dictionary.

Using map() with split

This method uses map() and split to process the string and convert it into a dictionary.

# Input string
s = "a:1,b:2,c:3"

# Converting to dictionary using map
d = dict(map(lambda x: (x.split(":")[0], int(x.split(":")[1])), s.split(",")))

print(d)

{'a': 1, 'b': 2, 'c': 3}

Explanation:

• The string is split by commas into a list of key-value pairs.
• map() applies a lambda function to split each pair by a colon and convert the value to an integer.
• The dict() function creates a dictionary from the mapped pairs.

Using For Loop

This method uses a simple for loop to build the dictionary.

# Input string
s = "a:1,b:2,c:3"

# Converting to dictionary using a loop
d = {}
for item in s.split(","):
    k, v = item.split(":")
    d[k] = int(v)

print(d)

{'a': 1, 'b': 2, 'c': 3}

Explanation:

• The string is split by commas to get the key-value pairs.
• Each pair is split by a colon to separate the key and value.
• The key-value pair is added to the dictionary after converting the value to an integer.

Using Regular Expressions

This method uses the re module to extract key-value pairs from the string.

import re

# Input string
s = "a:1,b:2,c:3"

# Extracting key-value pairs using regex
matches = re.findall(r'(\w+):(\d+)', s)
d = {k: int(v) for k, v in matches}

print(d)

{'a': 1, 'b': 2, 'c': 3}

Explanation:

• A regular expression matches key-value pairs in the string.
• re.findall() returns a list of tuples containing the keys and values.
• A dictionary comprehension converts the tuples into a dictionary, with the values cast to integers.