Use a variable to access key in struct

Question

I have a struct like so :

struct test {
    string a;
    string b;
}

and a mapping like this:

mapping (address => test) public tests;

I want to have a function to update the struct like this:

function updateStruct (string _paramName, string _newValue) {
  tests[msg.sender].(_paramName) = _newValue; // this is the line that shows the logic but doesn't work in compilation
}

How can I do this?

Answer 1

Solidity currently (v0.8) does not support accessing properties via magic variables.

You'll need to access the properties directly.

function updateStructA(string memory _newValue) public {
    tests[msg.sender].a = _newValue;
}

function updateStructB(string memory _newValue) public {
    tests[msg.sender].b = _newValue;
}