第132篇 mapping 中的删除操作

Posted 2022-11-24 wonderBlock

合约示例：

// SPDX-License-Identifier: MIT
 
pragma solidity 0.8.3;
 
contract mappingScores 
 
    mapping(string => uint256) public scores;
    string[] names;                                  // 必须记录所有的key
 
    function addScore(string memory name, uint256 score) public 
        scores[name] = score;
        names.push(name);
    
 
    function getScore(string memory name) public view returns(uint256) 
        return scores[name]; 
    
	
    function clear() public 
        while (names.length > 0) 
            delete scores[names[names.length - 1]];  // 根据key逐一删除
            names.pop();