Delete all elements from an array?

Question

I am writing a smart contract to be the backend of a game. Instead of using a mapping, I have decided to use an array to store the addresses of accounts who have paid my contract. (I know it is common practice to use a mapping for this but I find them to be confusing)

address[] paidPlayers;

As players join, their address is added via the following function.

function addPlayer(address player) constant returns (address[]) {
   paidPlayers.push(player);
   return paidPlayers;
}

Periodically, when a round in the game is completed, I want my contract to reset. I thus need a way of emptying my paidPlayers array. How is this done in solidity? Is there anything like the javascript

paidPlayers = [];

I have found methods for deleting a specific element but not the array as a whole.

Answer 1

From Solidity Documentation Tips and Tricks

Use delete on arrays to delete all its elements.

delete paidPlayers;

This is exactly the same as paidPlayers.length = 0

Answer 2

You can manually set the array length to 0 with:

paidPlayers.length = 0;

This will clear all entries in the array.

Update: starting with Solidity v0.6, the length member is read-only. You can no longer delete an array by setting the length to zero.

Answer 3

you can assign the array to a new empty array

   paidPlayers=new address[](0);

Answer 4

You can manipulate the array using assembly assuming it's stored in memory...

function _resizeArray(
    address[] memory array,
    uint256 size
) internal pure {
    assembly {
        mstore(array, size)
    }
}