3

I am looking for a way to get substring of a String. I am looking for an equivalent of this Java method. I am ok to use libraries but did not find it in solidity-stringutils.

public String substring(int startIndex, int endIndex)
3

The solidity documentation states, that there is no built in string manipulation available. Nevertheless, we can convert a string to a byte array and do the manipulation manually:

function substring(string str, uint startIndex, uint endIndex) constant returns (string) {
    bytes memory strBytes = bytes(str);
    bytes memory result = new bytes(endIndex-startIndex);
    for(uint i = startIndex; i < endIndex; i++) {
        result[i-startIndex] = strBytes[i];
    }
    return string(result);
}

Disclaimer: this method works for ASCII strings, but not for characters that are encoded with multiple bytes in UTF-8 (e.g. umlaute).

  • Here's a fiddle so you can play around with it: ethfiddle.com/-IaBg6dld7 – James Duffy Nov 24 '17 at 9:30
  • Thank you, Nicci and James for making the community better. I was not aware of ethfiddle. Very helpful. – Titu Nov 24 '17 at 16:16

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