String concatenation in solidity

Question

how do i concatenate strings in solidity?

var str = 'asdf'
var b = str + 'sdf'

seems not to work..

I looked up the documentation (https://github.com/ethereum/wiki/wiki/Solidity-Tutorial#elementary-types-value-types) and there is not much mentioned about string concatenation. But it is stated that it works with the dot ('.') ?

"[...] a mapping key k is located at sha3(k . p) where . is concatenation."

Answer 1

A library can be used, for example:

import "github.com/Arachnid/solidity-stringutils/strings.sol";

contract C {
  using strings for *;
  string public s;

  function foo(string s1, string s2) {
    s = s1.toSlice().concat(s2.toSlice());
  }
}