I'm learning to code in solidity and have started learning through making an ERC-20 token. I want to be able to see who is holding the tokens without using a for loop. So far I've mapped each address to see if they're a holder or not. But have no idea how to list all items in that map that are true for let's say a lottery or giving holders more tokens, etc.
mapping(address => bool) private isHolder;
I'm new so any help appreciated,