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  • ethereum(以太坊)(十一)--字节数组(二)

    pragma solidity ^0.4.0;
    
    
    contract test {
        uint [5] T =[1,2,3,4,5] ;//固定长度的数组:可修改数组内值大小,不支持push,不可更改长度
    
        /*
        contract test {
        uint [] T = new uint[](5); //ParserError: Expected identifier but got 'storage'
        //全局数组,默认创建在storage中,无法创建在memory中,长度可修改
        function setlength(uint aa){
            uint [] memory a = new uint[](5);
            bytes [] memory b = new bytes[](5);
            //TypeError: Type bytes memory[] memory is not implicitly
            //convertible to expected type bytes storage ref[] storage pointer.
            //函数内创建数组,需要指定存储在memory中,a.length不可更改
            //a.length = 10; // TypeError: Expression has to be an lvalue
            a[2] = 5;
            }
        }
        */
        function setValue(uint para){
            T[0] = para;
        }
        /*
        uint [] T =[1,2,3,4,5] ; //动态长度的数组:可修改数组内值大小,支持push,可更改长度
    
        /*
        uint [] T1 = new uint[](5);
    
        constructor() public{
            for (uint i;i<T1.length;i++){
                T1[i] = i;
            }
        }
        */
        function setlenth(uint para){
            T.length = 6;
        }
    
        function addvalue(uint para){
            T.push(3);
        }
        */
    
        function setValue1(){
            T[0] = 10;
        }
        function getValue() constant returns(uint){
            return T.length;
        }
    
        function get1Value() constant returns(uint){
            return T[0];
        }
    }
    
    
    pragma solidity ^0.4.0;
    
    
    contract test {
        //二维数组
        uint [2][3] T = [[1,2],[2,3]];
        /*
          1,2
          2,3
          0,0
        */
    
        uint [2][] T1 = new uint[2][](5);
    
        /*[i][j] T.length = j
        0,0
        0,0
        0,0
        0,0
        0,0
        */
        function getlenth() constant returns(uint){
            return T.length; //3
        }
    
        function getlenth1() constant returns(uint){
            return T1.length; //5
        }
    
        function get1lenth() constant returns(uint[2][]){ //输出二维数组
            return T1; //5
        }
    }
    
    pragma solidity ^0.4.0;
    
    contract test {
        function setValue() public{
    
            g([1,2,3]); //uint8
            //TypeError: Invalid type for argument in function call.
            //Invalid implicit conversion from uint8[3] memory to uint256[3] memory requeste
    
            g([uint(1),2,3]);
        }
        //uint 256
        function g(uint[3] data){
        }
    
        uint [] x1 = [uint(1),2,3];
        //storage:可变数组    memory:固定数组
        function get1() public{
            uint [] memory x = [uint(1),2,3];
            //memory:可变数组    memory:固定数组
            //在函数内部,memory类型的固定长度的数组不可直接赋值给storge/memory类型的可变数组
            //TypeError: Invalid type for argument in function call.
            //Invalid implicit conversion from uint8[3] memory to uint256[3] memory requested
        }
        function get1() public constant returns(uint[]){
            return x1; //uint256[]: 1,2,3 == [1,2,3]
            //uint [] memory x = [uint(1),2,3];
            //TypeError: Invalid type for argument in function call.
            //Invalid implicit conversion from uint8[3] memory to uint256[3] memory requested
        }
    
        pragma solidity ^0.4.0;
    
    
    contract test {
    
        bytes3 public b = 0x123456; //bytes3: 0x123456
    
        byte[3] public b1; //b1=0x000000  可直接通过索引进行查询
    
        bytes public b2= new bytes(3); //bytes: 0x000000 == byte[] public b3 = new byte[](3)
    
        byte[] public b3 = new byte[](3); // 0x000000 可直接通过索引进行查询
    
        /*
        function setb() public{
            b[0] =0x01;
        }
        */
    
        function setb1() public{
            b1[0] =0x01;
        }
    
        function setb2(bytes aa)public {
            for (uint i;i<aa.length;i++){
                b2.push(aa[i]);
            }
        }
    }
        /*
        总结:创建固定大小字节数组/可变大小字节数组
        固定大小字节数组:
          bytes0~bytes32:长度不可变,内容不可修改
          byte[len] b   :长度不可变,内容可以修改
        可变大小字节数组:可直接通过索引进行查询
          bytes b = new bytes(len) == byte[] b  = new byte[](len)
        特殊的可变字节数组:
          string :bytes() 通过bytes转换,length获取长度,通过索引修改相应的字节内容
        固定大小字节数组 -> 可变大小字节数组
          bytes3 a;
          bytes [] b = new bytes[a.length]
          for (uint i;i<a.length;i++){
              b[i] = a[i]
          }
          return b;
    
        uint [5] T =[1,2,3,4,5] ;//固定长度的数组:可修改数组内值大小,不支持push,不可更改长度
        uint [] T =[1,2,3,4,5] ; //动态长度的数组:可修改数组内值大小,支持push,可更改长度
    
        uint [] T = new uint[](5); //ParserError: Expected identifier but got 'storage'
        //全局数组,默认创建在storage中,无法指定在memory中,长度可修改
    
        //函数内创建数组,需要指定存储在memory中,a.length不可更改
    
        uint [] x1 = [uint(1),2,3] //[uint(1),2,3] = [1,2,3];
        //storage:可变数组    memory:固定数组
        */
    }
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  • 原文地址:https://www.cnblogs.com/eilinge/p/9980241.html
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