i have a binary string as follows "0101" i want to save it as binary file on disk using python

Sure, here is a step-by-step guide on how to save a binary string to a binary file using Python:

1. First, you need to convert your binary string to bytes. Python has a built-in function for this called int.to_bytes(). This function converts an integer to a bytes object.

binary_string = "0101"
# Convert binary string to integer then to bytes
binary_bytes = int(binary_string, 2).to_bytes((len(binary_string) + 7) // 8, 'big')

2. Now, you can write this bytes object to a file. You can use the write() method of a file object to write the bytes. Make sure to open the file in binary mode (by using 'wb' as the mode).

with open('binary_file', 'wb') as f:
    f.write(binary_bytes)

Here is the complete code:

binary_string = "0101"
binary_bytes = int(binary_string, 2).to_bytes((len(binary_string) + 7) // 8, 'big')

with open('binary_file', 'wb') as f:
    f.write(binary_bytes)

This code will create a file named 'binary_file' in the same directory as your Python script, and write the binary data to it.