Explicit type conversion not allowed from “string memory” to “uint256”

Question

I'm using an oracle to get results from a custom api. The result is in string by default. I want to convert it to uint256, so that I can perform basic arithmetic functions.

Here's my code:

function __callback(bytes32 myid, string result) public{
       if (msg.sender != provable_cbAddress()) revert();
       uint256 points = uint(result); //Error here
       balanceOf[pointsAllowance[myid]] = points;
       remSupply = remSupply - points;
       emit LogPriceUpdated(points);
}

Answer 1

You are using OraclizeLib library correct? If yes, this library has defined parseInt method inside of it. Then your function can be used like this without problems:

function __callback(bytes32 myid, string result) public{
    if (msg.sender != provable_cbAddress()) revert();
    
    uint256 points = parseInt(result);
    balanceOf[pointsAllowance[myid]] = points;
    remSupply = remSupply - points;
    
    emit LogPriceUpdated(points);
}