Python memoryview()

The memoryview() function in Python returns a memory view object that exposes the internal data of an object in a byte-wise manner, without making a copy.

Syntax

memoryview(obj)

Parameters

• obj: The object whose internal data is to be exposed. It can be a bytes object, a bytearray object or any object that implements the buffer protocol.

Return Value

The memoryview() function returns a memory view object that can be used to access the internal data of the object. The memory view supports slicing, indexing and iteration operations.

Example

# Create a bytes object
b = bytes([1, 2, 3, 4, 5])

# Create a memory view object
mv = memoryview(b)

# Print the memory view
print(mv)

# Print the first byte
print(mv[0])

# Update the first byte
mv[0] = 0

# Print the updated bytes object
print(b)

Output:

<memory at 0x7f152b7d0dc0>
1
b'\x00\x02\x03\x04\x05'

In the above example, we create a bytes object b and a memory view object mv using the memoryview() function. We print the memory view object, which returns a memory address. We access the first byte of the memory view using indexing and print its value. We update the first byte of the memory view and print the updated bytes object b, which shows that the first byte has been changed to 0.

Conclusion

The memoryview() function in Python is a powerful tool for accessing and manipulating the internal data of objects in a memory-efficient manner. It can be used to avoid unnecessary memory copies in applications that deal with large amounts of data.