[Ethereum] How to concat a double quote into a string in Solidity

soliditystring

I am looking for a solution to concat double quotes ("") into a string in Solidity.

What I need looks like this:

'{"id":idHere,"Lname":lname,"Fname":fname}'

All I get is sth like '{\"id\":idHere,\"Lname\":lname,\"Fname\":fname}'

PS: idHere, lname and fname are variables not constant value.

Best Answer

There is a strConcat() function in the usingOraclize contract that you are most likely inheriting from. You could use it like this:

  function queryString(
    uint256 _dynamicVariable
  ) 
    internal
    returns (string)
  {
    return strConcat(
      apiPrefix, // https:// or something like that
      encryptedApiComponent, // my example encrypts the domain
      "}", // closing part of oraclize query
      uint2str(_dynamicVariable), // also from oraclize 
      apiSuffix
    );
  }

Related Solutions

Go-Ethereum – Uncaught Error: new BigNumber() Not a Base 16 Number

Base 16 is hexadecimal. The variable iPos you're giving to getFirstname is base 10 IE "0"

Hexademical is 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F <-- Sixteen positions.

Demical is 0,1,2,3,4,5,6,7,8,9 <-- Ten positions.

The number zero in Base 16 is 0x0.

Solidity – How to Extract (Slice) Characters from a String

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

Best Answer

Related Solutions

Go-Ethereum – Uncaught Error: new BigNumber() Not a Base 16 Number

Solidity – How to Extract (Slice) Characters from a String

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