Append Data To Binary File In Python

We are given a binary file and our task is to append data into that binary file in Python using different approaches. In this article, we will see how we can append data to binary file in Python.

Append Data to Binary File in Python

below, are the examples of Append Data To Binary File In Python:

• Appending String Datatype
• Append List of Integers
• Append Data from Another binary File

Appending String Datatype To Binary File In Python Programming

In this example, below code opens the binary file ‘binary_file.bin’ in append mode, allowing new data to be added without overwriting existing content. It defines binary data ‘data’ to be appended and writes it to the file.

Python3

# Opening the created binary file in append mode
with open('binary_file.bin', 'ab') as file:
    # Data to append
    data = b'New data to append\n'

    # Writing the data to the file
    file.write(data)

print("Data has been appended to the binary file.")

Output

Data has been appended to the binary file.

Appending a String to the binary file

Append List of Integers To Binary File In Python Programming

In this example, below code appends a list of integers [1, 2, 3, 4, 5] to the binary file ‘binary_file.bin’. Inside the loop, each integer is converted to a 4-byte big-endian representation using to_bytes method, and then these byte sequences are written to the file.

Python3

data = [1, 2, 3, 4, 5]

# Opening the same binary file in append mode
with open('binary_file.bin', 'ab') as file:
    # Converting integers to bytes and append to the file
    for num in data:
        file.write(num.to_bytes(4, byteorder='big'))

Output

integers appended from a list to a binary file

Append Data from Another Binary File In Python Programming

Step 1: Create New File code

below code creates a new binary file ‘another_binary_file.bin’ and writes the sample data, which is a byte-encoded string containing the message “Hello, this is another binary file!”. The file is opened in binary write mode (‘wb’) to ensure proper handling of binary data.

Python3

# Creating another binary file
with open('another_binary_file.bin', 'wb') as file:
    # Sample data
    data = b'\nHello, this is another binary file!\n'

    # Writing the data to the file
    file.write(data)

Output

New binary file created

Inside the new binary file

Step 2: Append Data to Binary File

Below code reads the contents of the binary file ‘another_binary_file.bin‘ into the variable `binary_data` using binary read mode (‘rb‘). It then appends this binary data to the original binary file ‘binary_file.bin‘ in append mode (‘ab’). This allows the data from one binary file to be saved and appended to another.

Python3

# Saving the data from one binary file
with open('another_binary_file.bin', 'rb') as source_file:
    binary_data = source_file.read()

# Writing the data of the previous file in the original file
with open('binary_file.bin', 'ab') as destination_file:
    destination_file.write(binary_data)

Output

Data added from the new file to the original file

Conclusion

In conclusion , Appending data to a binary file in Python is a useful operation when working with non-textual data or complex data structures. The ability to efficiently add new data while preserving the existing structure makes binary files a preferred choice for various applications. Understanding the syntax and advantages of appending data to binary files empowers developers to handle diverse data storage scenarios in their Python projects.