Solidity: extracting (slicing) characters from a string

Question

Perhaps a double, but I couldn't find an answer here, and neither in strings library.

I have a string public string = "ABCDEFG"

I need to put together a function that iterates through the characters of the string and returns the characters that are in between the input numbers.

for example, function getSlice(uint256 begin, uint256 end) would return CDE if passed 2 and 6.

What would be the best way to create such a function?

Answer 1

You can do this:

pragma solidity 0.4.24;

contract test{

    function getSlice(uint256 begin, uint256 end, string text) public pure returns (string) {
        bytes memory a = new bytes(end-begin+1);
        for(uint i=0;i<=end-begin;i++){
            a[i] = bytes(text)[i+begin-1];
        }
        return string(a);    
    }


}

The variable text is the text that you want to slice.

Hope it helps