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# How to write a function to find values to decode a hidden text of an image BMP file

I'm trying to find an appropriate value for p & q to decode a hidden text of an image BMP file. The relevant code is as follows: def est_extract(): image_byte_array = est_get_bytes_containing_message() header_len = 54 message_bit_array = est_extract_bits_from_image( image_byte_array, header_len, p, q ) message_byte_array = est_convert_bits_to_bytes( message_bit_array ) est_write_message_text( message_byte_array ) if __name__ == '__main__': est_extract() i need to do it by following the steps below: **i need to write a function called est_bit_proportion which takes a Python array as an argument and computes the proportion of ones in it. And I am going to apply this to the existing message_bit_array for a particular choice of values for p and q. **A code which will try different values of p and q, namely all combinations of p = 1, 2, 3 and q = 1, 2, 3. There are thus nine combinations which I am going to try. **For each combination of p and q, you are going to run function est_bit_proportion to find the proportion of ones. **If the proportion of ones for some combination is less than 1 and greater than 0.5, I have the answer. Save those values of p and q and continue with the loop. So far I have tried with below-mentioned code for a in range(1, 4, 1): for b in range(1, 4, 1): bp = a/b print( "p =", a, "q =", b, "bp =", "%6.3f" % bp) if (bp > .5 and bp < 1): p = a q = b print( "The answer is:", "p =", p, "q =", q) But it's not working properly. The output is looking like below: p = 1 q = 1 bp = 1.000 p = 1 q = 2 bp = 0.500 p = 1 q = 3 bp = 0.333 p = 2 q = 1 bp = 2.000 p = 2 q = 2 bp = 1.000 p = 2 q = 3 bp = 0.667 The answer is: p = 2 q = 3 p = 3 q = 1 bp = 3.000 p = 3 q = 2 bp = 1.500 p = 3 q = 3 bp = 1.000 It would be really great if someone helps me to find the appropriate way to solve it.

13th Feb 2020, 10:01 PM
Earl 