solidity语言6

映射

可以认为是哈希，格式 mapping(_KeyType => _ValueType)

pragma solidity ^0.4.0;

contract MappingExample {
    mapping(address => uint) public balances;

    function update(uint newBalance) public {
        balances[msg.sender] = newBalance;
    }
}

contract MappingUser {
    function f() public returns (uint) {
        MappingExample m = new MappingExample(); // 存储在memory
        m.update(100);
        return m.balances(this);
    }
}