String array in solidity - ethereum

Question

I came across quite a common problem that it seems I can't solve elegantly and efficiently in solidity.
I've to pass an arbitrary long array of arbitrary long strings to a solidity contract.
In my mind it should be something like
function setStrings(string [] row)
but it seems it can't be done.
How can I solve this problem?

Answer 1

This is a limitation of Solidity, and the reason is that string is basically an arbitrary-length byte array (i.e. byte[]), and so string[] is a two-dimensional byte array (i.e. byte[][]). According to Solidity references, two-dimensional arrays as parameters are not yet supported.
Can a contract function accept a two-dimensional array?
This is not yet implemented for external calls and dynamic arrays - you can only use one level of dynamic arrays.
One way you can solve this problem is if you know in advanced the max length of all of your strings (which in most cases are possible), then you can do this:
function setStrings(byte[MAX_LENGTH][] row) {...}

Answer 2

December 2021 Update
As of Solidity 0.8.0, ABIEncoderV2, which provides native support for dynamic string arrays, is used by default.
pragma solidity ^0.8.0;
contract Test {
string[] public row;
function getRow() public view returns (string[] memory) {
return row;
}
function pushToRow(string memory newValue) public {
row.push(newValue);
}
}

Answer 3

String arrays as parameters aren't supported yet in solidity.

Answer 4

You can convert the array elements to a byte string and then deserialize that byte string back to the array inside the function. Although this can prove to be quite expensive you can try it if you don't have a choice. You can follow this short article to serialize/deserialize any datatype in solidity.

Answer 5

all solutions you need:-
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.1;
contract HelloWorld {
string[] strings;
// push one string to array
function pushToStrings(string memory _data) public{
strings.push(_data);
}
//get all the strings in array form
function GetAllStrings() view public returns(string[] memory){
return strings;
}
//get nth string of strings array
function GetNthStrings(uint x) view public returns(string memory){
return strings[x];
}
//push array of strings in strings
function pushStringsArray(string[] memory someData) public{
for (uint i=0; i < someData.length; i++) {
strings.push(someData[i]);
}
}
//change whole strings, take array of strings as input
function changeWholeString(string[] memory someData) public{
strings=someData;
}
}

Answer 6

string array is not available in Solidity
because String is basically array of character
Nested dynamic arrays not implemented

Answer 7

There are two types arrays in solidity: static array and dynamic array.
declaration of array
static array: These has fixed size.
int[5] list_of_students;
list_of_students = ["Faisal","Asad","Naeem"];
we access the values using index number
Dynamic arrays: The size of these arrays dynamically increases or decreases.
int[] list_of_students;
list_of_students.push("Faisal");
list_of_students.push("Asad");
list_of_students.push("Smith");
we can access the value using index number.
push and pop function is used to insert and delete the values. length function is used to measure the length of the array.

Answer 8

It can be done by using
pragma experimental ABIEncoderV2;
at the top of your contract you may then use dynamic arrays of strings. Ex.
string[] memory myStrings;

Answer 9

This is an example contract to manage the array push, get, getAll,
and remove
pragma solidity ^0.8.4;
contract Array {
string[] private fruits = ["banana", "apple", "avocado", "pineapple", "grapes"];
function push(string memory item) public {
fruits.push(item);
}
function get(uint256 index) public view returns (string memory) {
return fruits[index];
}
function remove(uint256 index) public returns (bool) {
if (index >= 0 && index < fruits.length) {
fruits[index] = fruits[fruits.length - 1];
fruits.pop();
return true;
}
revert("index out of bounds");
}
function getAll() public view returns (string[] memory) {
return fruits;
}
}