如何 return 嵌套数组

Question

我正在尝试 return 嵌套数组 on solidity 错误消息说

"browser/HISTORYMultipleStateMach.sol:22:16: TypeError: Index expression cannot be omitted. return myArray[]; ^-------^" "browser/HISTORYMultipleStateMach.sol:22:16: TypeError: Index expression cannot be omitted. return myArray[]; ^-------^" Can someone tell me what is wrong? Thank you enum State{ A, B, C }

    State[] curState;
    State[][] myArray;

    uint i=0;
    constructor(uint Machines)public{
        for(i=0;i<Machines;i++){
            curState.push(State.A);
            myArray.push(curState);
        }enter code here
    }


    function historyOfStateMachine() public{
        return myArray[];
    }


   function historyOfStateMachine() public{
        return myArray[];
    }

Answer 1

为了return整个数组，你应该删除return myArray[];

中的[]

此外，还不能 return two levels of dynamic arrays。

从 version 0.4.19 of solidity 开始，您可以激活对任意嵌套的实验性支持使用指令 pragma experimental ABIEncoderV2; 的数组。在这种情况下，您的代码将如下所示：

pragma solidity ^0.4.19;
pragma experimental ABIEncoderV2;

contract MyContract {
    enum State{ A, B, C }

    State[] curState;
    State[][] myArray;

    uint i=0;

    constructor(uint Machines)public{
        for(i=0;i<Machines;i++){
            curState.push(State.A);
            myArray.push(curState);
        }
    }

    function historyOfStateMachine() public view returns (State[][]) {
        return myArray;
    }

}

如何 return 嵌套数组

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