How can I get the return values?

Question

I have a function with 4 return values which are in different types. Within the same contract, I want another function get this return values. For example,

function myFunction1() returns (uint, string, address){
       ......
}
funtion myFunction2(){
    String s = myFunction1();
}

I want string s get the second value returned by myFunction1. How can I do that?

Answer 1

See the section on "destructuring assignments and returning multiple values" in the Solidity documentation.

As an example:

    function f() returns (uint, bool, uint) {
        return (7, true, 2);
    }

    function g() {
        // Declares and assigns the variables. Specifying the type explicitly is not possible.
        var (x, b, y) = f();
    }

However, it should be noted that you can't return dynamically sized values, as per this previous answer.

Answer 2

Here is the official example from the latest version of Solidity:

pragma solidity >0.4.23 <0.5.0;

contract C {
    uint[] data;

    function f() public pure returns (uint, bool, uint) {
        return (7, true, 2);
    }

    function g() public {
        // Variables declared with type and assigned from the returned tuple.
        (uint x, bool b, uint y) = f();
        // Common trick to swap values -- does not work for non-value storage types.
        (x, y) = (y, x);
        // Components can be left out (also for variable declarations).
        (data.length,,) = f(); // Sets the length to 7
    }
}

Note that you can now use dynamically sized values.

Furthermore, the var keyword has been deprecated.