Python | bytearray() function

bytearray() method returns a bytearray object in Python which is an array of given bytes. It gives a mutable sequence of integers in the range 0 <= x < 256. 

Syntax of bytearray() Function in Python

Python bytearray() function has the following syntax:

Syntax: bytearray(source, encoding, errors)

Parameters:

• source[optional]: Initializes the array of bytes
• encoding[optional]: Encoding of the string
• errors[optional]: Takes action when encoding fails

Returns: Returns an array of bytes of the given size.

source parameter can be used to initialize the array in few different ways. Let’s discuss each one by one with help of examples. 

Python bytearray() Function Examples

Let us see a few examples, for a better understanding of the bytearray() function in Python.

bytearray() Function on String

In this example, we are taking a Python String and performing the bytearray() function on it. The bytearray() encodes the string and converts it to byte array object in python using str.encode().

Python3

str = "Geeksforgeeks"

# encoding the string with unicode 8 and 16
array1 = bytearray(str, 'utf-8')
array2 = bytearray(str, 'utf-16')

print(array1)
print(array2)

Output:

bytearray(b'Geeksforgeeks')
bytearray(b'\xff\xfeG\x00e\x00e\x00k\x00s\x00f\x00o\x00r\x00g\x00e\x00e\x00k\x00s\x00')

bytearray() Function on an Integer

In this example, an integer is passed to the bytesrray() function, which creates an array of that size and initialized with null bytes and return byte array object in Python.

Python3

# size of array
size = 3

# will create an array of given size
# and initialize with null bytes
array1 = bytearray(size)

print(array1)

Output:

bytearray(b'\x00\x00\x00')

bytearray() Function on a byte Object

In this example, we take a byte object. The read-only buffer will be used to initialize the bytes array and return the byte array object in Python.

Python3

# Creates bytearray from byte literal
arr1 = bytearray(b"abcd")

# iterating the value
for value in arr1:
    print(value)

# Create a bytearray object
arr2 = bytearray(b"aaaacccc")

# count bytes from the buffer
print("Count of c is:", arr2.count(b"c"))

Output:

97
98
99
100
Count of c is: 4

bytearray() Function on a List of Integers

In this example, We take a Python List of integers which is passed as a parameter to the bytearray() function.

Python3

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

# iterable as source
array = bytearray(list)

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

Output:

bytearray(b'\x01\x02\x03\x04')
Count of bytes: 4

bytearray() Function with no Parameters

If no source is provided to the bytearray() function, an array of size 0 is created and byte array object is returned of that empty array.

Python3

# array of size 0 will be created

# iterable as source
array = bytearray()

print(array)

Output:

bytearray(b'')