1
contract Bar{

    struct Foo{
        uint x;
    }
    mapping(uint => Foo[]) foo;

    function add(uint id, uint _x) public {
        foo[id].push(Foo(_x));
    }

    function get(uint id, uint index) public returns(uint){
        return foo[id][index].x;
    }
}

I'm trying to call all the index value. Like there will be return function which will return all the total index value.

And If suppose I wish to return the last 10 data of address ID + Index value. How would I call that.

Because I need to enter the index value, but if someone do not know the index value. Then it will be difficult.

1

To get the last ten values you could add this function:

function get_last_ten(uint id) public returns(uint[10]){
    uint[10] memory lastItems;
    for(uint i=0;i<10;i++){
        if(foo[id].length>i){
            lastItems[i] = foo[id][foo[id].length-i-1].x;
        }
    }
    return lastItems;
}

This will return an array of ten values the first value is the last element in the specific address id of foo.

hope this helps

  • Thanks a lot. This really worked. Thankyou #Jaime for your help. – shrey bhardwaj Aug 13 '18 at 9:13
0

You would derive a different solution, but I would suggest you 2 different ways that I would prefer mostly.

pragma solidity ^0.4.24;

contract StackExchangeSol{

    struct Foo{
        uint x;
    }

    mapping(uint => Foo[]) foo;
    //Solution-2
    uint[] indexOf;
    //Solution-2

    function add(uint id, uint _x) public {
        foo[id].push(Foo(_x));
        //Solution-1
        count++;
        //Solution-1
    }

    function get(uint id, uint index) public view returns(uint){
        return foo[id][index].x;
    }
    //Solution-1
    uint count;
    constructor() public{
        count=0;
    }
    //Solution-1


    //Solution-2
    function getLenOf() public view returns(uint){
        return indexOf.length;

    }
    //Solution-2      
}
  • But it is not returning any value. – shrey bhardwaj Aug 13 '18 at 6:45

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