Python bytes()

Python bytes() function return an immutable byte-represented object of given size and data.

The bytes() method provides immutable(cannot be changed) sequence of objects in the range of 0 <= x < 256

If you want a mutable version, you can use the bytearray() method.

bytes() Syntax 

The syntax of the bytes() method is:

bytes([source[, encoding[, errors]]])

bytes() Parameters

The bytes() method takes three optional parameters.

  • source (Optional) – Initializes the array of bytes
  • encoding (Optional) – in case if the source is a string, the encoding of the string.
  • errors (Optional) – An action to take if the encoding conversion fails.  

The source parameter can be of any below type as follows.

TypeDescription
StringConverts the given string into bytes using str.encode(). In the case of a string, you must also pass encoding as an argument and, optionally errors
IntegerCreates an array of provided size and initializes with null bytes
ObjectA read-only buffer of the object will be used to initialize the byte array
IterableCreates an array of size equal to the iterable count and initialized to the iterable elements. The iterable should be of integers and the range should be in between 0 <= x < 256
No source (arguments)An array of size 0 is created.

bytes() Return Value

The bytes() function returns an array of bytes of the given size and initializes values.

Example 1: Create a byte of a given integer size

In the case of an integer, it creates an array of provided size and initializes with null bytes.

# size of array
size = 6

# bytes() will create an array of given size
# and initialize with null bytes
arr = bytes(size)

print(arr)

Output

b'\x00\x00\x00\x00\x00\x00'

Example 2: Convert string to bytes

Converts the given string into bytes using str.encode(). In the case of a string, you must also pass encoding as an argument and, optionally, errors.

# string declaration
string = "Hello World !!!"

# string with encoding 'utf-8'
arr1 = bytes(string, 'utf-8')
print(arr1)

# string with encoding 'utf-16'
arr2 = bytes(string, 'utf-16')
print(arr2)

Output

b'Hello World !!!'
b'\xff\xfeH\x00e\x00l\x00l\x00o\x00 \x00W\x00o\x00r\x00l\x00d\x00 \x00!\x00!\x00!\x00'

The string handling error is defined as:

String Error Handlers : 

  • strict: Raises the default UnicodeDecodeError in case of encoding failure.
  • ignore: Ignores the unencodable character and encodes the remaining string.
  • replace: Replaces the unencodable character with a ‘?’.

If you notice the strict type will raise an UnicodeEncodeError if the encoding fails as shown below.


from typing import Text


text = 'HellÖ WÖrld'
# Giving ascii encoding and ignore error
print("Byte conversion with ignore error : " +
      str(bytes(text, 'ascii', errors='ignore')))
 
# Giving ascii encoding and replace error
print("Byte conversion with replace error : " +
      str(bytes(text, 'ascii', errors='replace')))
 
# Giving ascii encoding and strict error throws exception
print("Byte conversion with strict error : " +
      str(bytes(text, 'ascii', errors='strict')))

Output

Byte conversion with ignore error : b'Hell Wrld'
Byte conversion with replace error : b'Hell? W?rld'

Traceback (most recent call last):
  File "c:\Projects\Tryouts\main.py", line 17, in <module>
    str(bytes(text, 'ascii', errors='strict')))
UnicodeEncodeError: 'ascii' codec can't encode character '\xd6' in position 4: ordinal not in range(128)

Example 3: Convert iterable list to bytes

Creates an array of size equal to the iterable count and initialized to the iterable elements. The iterable should be of integers, and the range should be in between 0 <= x < 256

# list of integers
lst = [1, 2, 3, 4, 5]

# iterable as source
arr = bytes(lst)

print(arr)
print("Count of bytes:", len(arr))

Output

b'\x01\x02\x03\x04\x05'
Count of bytes: 5

Example 4: If no source is passed to bytes()

If no source is passed into bytes(), an array of size 0 is created.

# array of size 0 will be created

# iterable as source
arr = bytes()

print(arr)

Output

b''
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