区块链学堂（22）：String 数组类型

我不是女神ヾ 2022-06-02 05:36 182阅读 0赞

String类型的官方定义

> String literals are written with either double or single-quotes (“foo” or ‘bar’). They do not imply trailing zeroes as in C; “foo”\` represents three bytes not four. As with integer literals, their type can vary, but they are implicitly convertible to bytes1, …, bytes32, if they fit, to bytes and to string.
> 
> String literals support escape characters, such as \\n, \\xNN and \\uNNNN. \\xNN takes a hex value and inserts the appropriate byte, while \\uNNNN takes a Unicode codepoint and inserts an UTF-8 sequence. 引用自[here][]

### String数组类型定义 ###

string[] strArr

### String数组的增删改查 ###

*  Step 1: 首先撰写一个String数组的contract和构造函数
    
        pragma solidity 0.4.10;
        contract Demo {
          string[] public strArr;
          function Demo() {
              strArr.push("init");
          }
        }
 *  Step 2: 添加一个Add function
    
        function Add(string str) {
              strArr.push(str);
          }
 *  Step 3: 添加一个Update function
    
        function Update(uint index, string str) {
              if (index > strArr.length-1) throw;
              strArr[index] = str;
          }
    
    大家注意一下，如果index>strArr.length-1, 此时应抛出异常
 *  Step 4: 添加一个ValueOf function
    
        function ValueOf(uint index) returns (string str){
              if (index > strArr.length-1) throw;
              return strArr[index];
          }
 *  Step 5: 添加一个DeleteAt function

function DeleteAt(uint index) {
            uint len = strArr.length;
            if (index > len-1) throw;
            for (uint i = index; i<len-1; i++) {
                strArr[i] = strArr[i+1];
            }
    
            delete strArr[len-1];
            strArr.length--;
        }

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原文：http://www.ethchinese.com/?p=1022

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[here]: http://solidity.readthedocs.io/en/develop/types.html
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[ethchinese.jpg]: http://www.ethchinese.com/wp-content/uploads/2017/02/ethchinese.jpg