mapping(uint => address) public Players;

can anybody help me how can I delete Players mapping. I wrote a lottery contract and I need to remove this mapping to reuse the contract.

I try this code but It doesn't work

    delete Players[playerId];

1 Answer 1


Solidity is not like the other languages. You can think of the storage as empty array so even if you have never used a mapping for eg. Players[12334] its value is not nil/null/nullptr it is the default value for the type. In your case the default value for address is the zero address (0x000.../address(0)). If you want to delete player it is enough to set it to the zero address.

  • yeah that works but still there is a problem . Let say my contract has 1 million player , In this case I should use for Loop and equal every address to zero. Is there a way to remove my mapping without using for loop ???
    – user83980
    Oct 23, 2021 at 5:22
  • Unfortunately there is no other way. And deleting all users is a corner case, most probably you will delete only one at a time and you will know which is its index. Oct 23, 2021 at 5:46

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