Python Binary files: Purpose of the to_bytes Method

The importance of the to_bytes method is explained here as to why it is required while writing binary files in python and the three arguments – length, byteorder, and signed.

Why do you need the to_bytes method?

While dealing with binary data, you’ll need to understand two methods to_bytes and from_bytes. These convert an integer to binary and from binary to an integer.

Writing and reading binary file

Here are two parts of the code you can find. The first part converts numeric to binary and writes to a file. Here, the file name is myfile.b

The second part reads binary data and converts it to an integer.

# Python Writing Binary Data
with open("myfile.b", 'wb') as b1:
    a=10
    b=a.to_bytes(2,byteorder='big',signed=True)
    b1.write(b)
   

# Python Reading Binary Data
with open("myfile.b", 'rb') as b2:
    b3=b2.read(2)
    c=int.from_bytes(b3,byteorder='big',signed=True)
    print(c)

The output.

10

** Process exited - Return Code: 0 **
Press Enter to exit terminal

Purpose of to_bytes and from_bytes

The purpose of to_bytes is to convert integers to binary, and from_bytes is to convert binary data to an integer. Both methods need three arguments: length, byteorder, and signed. Check out more in Python docs.

For length, valid values are 2, 4, 8, and so on, but the default is 1.
For byteorder, valid values are big and little. The big is the default value.
If the byteorder is big, the most significant byte is at the beginning of the byte array. If little, the most significant byte is at the end of the byte array.
For signed, valid values are True/False. True says minus is present in the input, and the False sign is not there. Here False is the default value.
The From_bytes method needs the first argument to be binary data.