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);

    }

}