If you receive a 7-bit string, you run the parity checks. The result (called the syndrome) is a binary number from 001 to 111. That number tells you exactly which bit to flip to fix the message.
This is not a tutorial on Python. This is an exploration of the mathematical bones of the digital age. Before Claude Shannon, the father of information theory, information was a philosophical or semantic concept. Shannon did something radical: he stripped meaning away entirely.
When your data corrupts, you are witnessing a violation of the Hamming distance. When your compression algorithm bloats instead of shrinks, you are witnessing low entropy.
Think of entropy as the "randomness temperature." High entropy (like white noise or scrambled text) means high information density. Low entropy (like a repeating loop of silence or a predictable string of zeroes) means you can compress it down to almost nothing. Coding Theory: The Art of Reliable Imperfection If information theory is about efficiency , coding theory is about survival .
If I tell you something you already know (e.g., "The sun will rise tomorrow"), I have transmitted very little information. If I tell you something shocking (e.g., "The sun did not rise today"), I have transmitted a massive amount of information.
Mathematically, the information content ( h(x) ) of an event ( x ) with probability ( p ) is:
Entropy is the average amount of information produced by a source. It is also the minimum number of bits required, on average, to encode the source without losing any information.