Python Binary Data Services

The struct module in Python provides functionality for converting between C structs and Python bytes objects. This is essential for binary data processing, file format handling, and network protocol implementation.

Format String Characters

The byte order, size, and alignment in format strings are controlled by these characters ?

Data Type Format Characters

These format characters map C types to Python types ?

Using Module-Level Functions

The pack() function converts Python values to bytes, while unpack() converts bytes back to Python values ?

import struct

student = (1, b'Rahul', 65.75)
packed = struct.pack('I 5s f', *student)
print('packed data:', packed)

unpacked = struct.unpack('I 5s f', packed)
print('unpacked data:', unpacked)

packed data: b'\x01\x00\x00\x00Rahul\x00\x00\x00\x00\x80\x83B'
unpacked data: (1, b'Rahul', 65.75)

Using the Struct Class

Creating a Struct object is more efficient when using the same format multiple times ?

import struct

student = (1, b'Rahul', 65.75)
s = struct.Struct('I 5s f')

packed = s.pack(*student)
print('packed:', packed)

unpacked = s.unpack(packed)
print('unpacked:', unpacked)

packed: b'\x01\x00\x00\x00Rahul\x00\x00\x00\x00\x80\x83B'
unpacked: (1, b'Rahul', 65.75)

Working with Named Tuples

You can convert unpacked data directly to a named tuple for better readability ?

import struct
from collections import namedtuple

student = (1, b'Rahul', 65.75)
packed = struct.pack('I 5s f', *student)

Student = namedtuple('Student', 'No Name Marks')
s1 = Student._make(struct.unpack('I 5s f', packed))
print(s1)
print(f"Student Number: {s1.No}, Name: {s1.Name.decode()}, Marks: {s1.Marks}")

Student(No=1, Name=b'Rahul', Marks=65.75)
Student Number: 1, Name: Rahul, Marks: 65.75

Conclusion

The struct module enables efficient binary data conversion between Python and C formats. Use module functions for simple operations or the Struct class for repeated operations with the same format.