Write Data in Binary Mode in Python

In Python, you can write data in binary mode using the built-in open() function with the mode set to 'wb'. This mode allows writing binary data such as images, audio files, or any raw byte sequences directly to a file.

Examples to Write Binary Files

1. Writing Binary Data to a File

In this example, we will write a sequence of bytes to a binary file.

main.py

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# Open a file in binary write mode
with open("binary_file.bin", "wb") as file:
    # Define binary data
    binary_data = b'\x48\x65\x6C\x6C\x6F'  # "Hello" in ASCII

    # Write binary data to file
    file.write(binary_data)

print("Binary data written successfully.")

Explanation:

  1. open("binary_file.bin", "wb"): Opens a file named binary_file.bin in binary write mode.
  2. b'\x48\x65\x6C\x6C\x6F': A byte sequence representing the ASCII characters of “Hello”.
  3. file.write(binary_data): Writes the binary data to the file.

Output:

binary_file.bin content:

2. Writing Binary Data from a Bytes Object

We can also write binary data created from a bytes object.

main.py

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# Open a file in binary write mode
with open("binary_file.bin", "wb") as file:
    # Create a bytes object from a list of integers
    numbers = bytes([65, 66, 67, 68, 69])  # Corresponds to "ABCDE"

    # Write binary data to file
    file.write(numbers)

print("Binary numbers written successfully.")

Explanation:

  1. bytes([65, 66, 67, 68, 69]): Converts a list of integers into a bytes object.
  2. file.write(numbers): Writes the byte sequence to the file.

Output:

binary_file.bin content:

3. Writing Binary Data from a String

We can convert a string into bytes using the encode() method and write it in binary mode.

main.py

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# Open a file in binary write mode
with open("binary_file.bin", "wb") as file:
    # Convert string to bytes
    text = "Sample Data. Binary Mode Writing."
    binary_text = text.encode('utf-8')

    # Write binary data to file
    file.write(binary_text)

print("String written in binary mode successfully.")

Explanation:

  1. text.encode('utf-8'): Converts the string into bytes using UTF-8 encoding.
  2. file.write(binary_text): Writes the encoded byte data to the file.

Output:

binary_file.bin content:

4. Writing Binary Data from an Image

We can copy an image file by reading and writing in binary mode.

main.py

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# Open the source image in binary read mode
with open("source_image.jpg", "rb") as source:
    # Read binary content
    image_data = source.read()

# Open a new file in binary write mode
with open("copied_image.jpg", "wb") as destination:
    # Write the binary data
    destination.write(image_data)

print("Image copied successfully in binary mode.")

Explanation:

  1. open("source_image.jpg", "rb"): Opens an image in binary read mode.
  2. image_data = source.read(): Reads the binary data.
  3. open("copied_image.jpg", "wb"): Opens a new image file in binary write mode.
  4. destination.write(image_data): Writes the copied binary content.

Output:

Image copied successfully in binary mode.

Conclusion

In this tutorial, we have covered various ways to write data in binary mode:

  1. Using wb mode in open() to write raw binary data.
  2. Writing a bytes object directly to a file.
  3. Encoding strings into binary format using encode().
  4. Reading and writing images in binary mode for file operations.