Best way to convert string to bytes in Python 3?
Hey Heenakhan,
Bytes vs. bytearray: Understanding the Nuances
The documentation for bytes might leave you wondering why it exists when bytearray seems to handle everything. Here’s a breakdown of the key differences:
Mutability:
bytes objects are immutable, meaning their content cannot be changed after creation. This aligns with Python’s philosophy of immutability for built-in sequence types like strings and tuples.
bytearray objects are mutable, allowing you to modify their contents after creation. This is useful when you need to dynamically work with byte data.
Constructor Flexibility:
Both bytes and bytearray offer various ways to initialize them: strings (with encoding), integers (specifying size), buffers, and iterables of integers.
However, bytes prioritizes clarity for string encoding. Using some_string.encode(encoding) is considered more Pythonic because it explicitly states the purpose: “encode this string with this encoding.”
Internal Workings:
In CPython, when you pass a unicode string to bytes, it ultimately calls the same function (PyUnicode_AsEncodedString) used by encode. So, using encode directly is just a slightly less direct approach.
Symmetry and Readability:
The concept of encoding and decoding is a two-way street. The inverse of unicode_string.encode(encoding) is byte_string.decode(encoding). Having a clear and consistent pattern for both operations enhances readability.
In essence:
Use bytes for string encoding when clarity and immutability are desired.
Use bytearray for working with mutable byte data that might need modifications.
While bytearray is powerful, bytes remains a valuable tool for specific use cases that prioritize readability and immutability.
Hello Heenakhan,
It’s easier than it is thought:
my_str = “hello world”
my_str_as_bytes = str.encode(my_str)
print(type(my_str_as_bytes)) # ensure it is byte representation
my_decoded_str = my_str_as_bytes.decode()
print(type(my_decoded_str)) # ensure it is string representation
you can verify by printing the types. Refer to output below.
<class ‘bytes’>
<class ‘str’>
Hello
To convert a string to bytes in Python 3, you can use the encode() method, which is the most common and Pythonic way. Here’s an example:
my_str = “hello world”
my_str_as_bytes = my_str.encode(‘utf-8’)
print(type(my_str_as_bytes)) # Outputs: <class ‘bytes’>
To convert back to string
my_decoded_str = my_str_as_bytes.decode(‘utf-8’)
print(type(my_decoded_str)) # Outputs: <class ‘str’>
Using encode() and decode() ensures clarity and is consistent with Python’s handling of string and byte data.
For more details, you can visit the discussion here.
Thank you 
stevediaz
1 Like
Hey Heena khan,
Converting Text to Bytes in Python
We saw how to convert a string (my_str) into a byte representation (my_str_as_bytes) suitable for storage or transmission. While the previous explanation was helpful, there’s a more concise and efficient approach.
The Power of Defaults:
In Python 3 (since version 3.0), the encode method cleverly defaults the encoding to ‘utf-8’ if no argument is provided. This encoding scheme effectively represents a wide range of characters.
Shortcut for Efficiency:
Therefore, the most streamlined way to achieve this conversion is:
Python
b = my_str.encode()
This approach not only reduces code by omitting the encoding argument but also offers a slight performance benefit. The reason lies in how Python handles the default value internally. Specifying ‘utf-8’ requires additional checks within the code, whereas the default translates to a null value in C code, leading to faster execution.