Convert byte string Key:Value Pair of Dictionary to String - Python

In Python, dictionary keys and values are often stored as byte strings when working with binary data or certain encoding formats, we may need to convert the byte strings into regular strings. For example, given a dictionary {b'key1': b'value1', b'key2': b'value2'}, we might want to convert it to {'key1': 'value1', 'key2': 'value2'}. Let's discusses multiple methods to achieve this.

Using Dictionary Comprehension

This method uses dictionary comprehension to iterate through each key-value pair, decoding the byte strings into regular strings.

a = {b'key1': b'value1', b'key2': b'value2'}
b = {k.decode(): v.decode() for k, v in a.items()}
print(b)

{'key1': 'value1', 'key2': 'value2'}

Explanation:

• a.items() retrieves all key-value pairs in the dictionary.
• For each pair, k.decode() and v.decode() convert the byte strings to regular strings.
• Dictionary comprehension creates a new dictionary with the converted values.

Let's explore some more ways and see how we can convert byte string key:value pair of dictionary to string.

Using Loop and dict.update()

This method uses a for loop to decode each key and value, updating the dictionary with string pairs.

a = {b'key1': b'value1', b'key2': b'value2'}
b = {}
for k, v in a.items():
    b[k.decode()] = v.decode()
print(b)

{'key1': 'value1', 'key2': 'value2'}

Explanation:

• A loop iterates through all key-value pairs in the dictionary.
• Both the key and value are decoded using decode() and added to a new dictionary b.
• This method is straightforward and avoids creating intermediate objects.

Using dict() with map()

This method uses the map() function to decode keys and values during dictionary construction.

a = {b'key1': b'value1', b'key2': b'value2'}
b = dict((k.decode(), v.decode()) for k, v in a.items())
print(b)

{'key1': 'value1', 'key2': 'value2'}

Explanation:

• map() applies decode() to each key and value while creating the dictionary.
• dict() constructs the final dictionary using the decoded key-value pairs.

Using copy()

This method creates a copy of the dictionary and modifies it in place by decoding its keys and values.

a = {b'key1': b'value1', b'key2': b'value2'}
b = a.copy()
for k in list(b.keys()):
    b[k.decode()] = b.pop(k).decode()
print(b)

{'key1': 'value1', 'key2': 'value2'}

Explanation:

• A copy of the dictionary is made to avoid modifying the original.
• The loop iterates through the keys, decoding both the keys and values and updating the new dictionary.
• This method works directly on the dictionary structure.

Using JSON Module for Decoding

json module can handle byte strings when converting the dictionary into a JSON string and back to a dictionary.

import json

a = {b'key1': b'value1', b'key2': b'value2'}

# Decode byte strings before converting to JSON
d = {k.decode(): v.decode() for k, v in a.items()}

# Use JSON dumps and loads
b = json.loads(json.dumps(d))
print(b)

{'key1': 'value1', 'key2': 'value2'}

Explanation:

• dictionary is converted to a JSON string using json.dumps().
• Byte string markers (b') are replaced with standard string markers (') and converted back to a dictionary using json.loads().
• This method is less direct but useful in certain cases.