this code require two input(_Id,_name) to get age i need to get name and age from input id only

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;
contract nestmap
    mapping(uint256=>mapping(string=>uint256)) public User;
    function adduser(uint256 _Id,string memory _name, uint256 _age)public {
function user(uint256 _Id,string memory _name)public view returns(uint256)
        return User[_Id][_name];
  • 1
    Your nested mapping describes a data structure where each id has a large number of string keys, and each of those maps to a uint256, so probably not what you want. It's roughtly key1 => key2 => value, hence two keys are requested. I voted for Yongjian's answer. That's probably what you want. Oct 19, 2022 at 21:12

1 Answer 1


You can try this:

pragma solidity 0.8.7;

contract nestmap {

    struct Person{
        uint256 age;
        string name;

    mapping (uint256 => Person) public User;

    function adduser(uint256 _Id, uint256 _age, string memory _name) public {
         User[_Id].age = _age;
         User[_Id].name = _name;

    function user(uint256 _Id) public view returns(Person memory) {
        return User[_Id];

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