Questions tagged [arrays]
Questions regarding the use of Arrays in solidity.
59
questions with no upvoted or accepted answers
3
votes
3answers
814 views
How to handle dynamic size string array in solidity?
I have a shop owner and a shop owner can have multiple products. I want to keep the products id in an array.
Also, A public method can return all the product id list of a shop owner.
I tried the ...
3
votes
0answers
200 views
Implement constant search function in Solidity or in Javascript?
I am working with Meteor + Web3. Is it recommendable to implement a constant search function in Solidity or to transfer the data into a javascript array each time to then search in it?
Thank you!
2
votes
0answers
40 views
Performing a C-like pointer increment in Solidity
I have a memory or calldata struct with an attribute of type byte[]. I want to have a memory variable with that data, except for the first n Bytes.
In C, you'd just write
typename variablename = ...
2
votes
1answer
74 views
How to return values from dynamic array push function?
How to fetch value from dynamic array push function? Below is the code of pushing function, but how will I fetching that array values?
contract PushStruct {
struct MyStruct {
uint field1;
...
2
votes
0answers
70 views
Why is putting data to storage more expensive during the deployment of contract than storing the same data by a method?
I am working with truffle and solidity (v0.4.23) and found out that when I pass in an argument of constructor some bigger amount of data (16kB) that are saved to storage of a smart contract, it is ...
2
votes
0answers
157 views
Global storage array - setting length on declaration vs inside a function
I have a global storage array of 64 entries, which I declare as follows:
uint256[64] globalArr;
However, its length really depends on a constant variable in my code:
uint8 constant MAX_VAL = 63;
...
2
votes
0answers
440 views
Why is dynamic array length not updated after addition of new element?
I created a struct as follows:
struct Node{ // each node models each device on the network
address nodeAdress; // adress of the node
uint trustValue; // trust value ...
2
votes
0answers
58 views
How does a plot “Gas price to call / memory allocated” looks like?
Pretty simple question: i.e. I have a dummy contract like this one:
contract simple {
uint[] dataArray;
function push_one_more() {
dataArray.push(1);
}
}
How does the cost of ...
1
vote
0answers
31 views
how to display a struct inside mapping inside struct in solidity on react js frontend
I have a mapping of struct (mapping (address => struct)) inside another struct. I'm having issue in how to display the struct in the front end while using Reactjs.
1
vote
1answer
24 views
arrays and structs for function arguments
A lot of contracts and libraries with functions that use arrays and structs for arguments. Structs can themselves include arrays, structs and mappings. For example:
function doSomething(MyStruct ...
1
vote
0answers
73 views
How to pass array parameter. Drizzle
Is there have a way to pass array parameter from the drizzle to my contract ?
I want to pass an array of uint[]
i have read a lot about getData() function and encodeABI but how to use it in Drizzle ?
1
vote
1answer
28 views
Use Values Returned from One Function in Another
need a little help if you can spare the time.
Making a little card game where people can collect "warrior" cards.
We'll have an initial 12 master "cards" that supply the initial traits for the ...
1
vote
0answers
182 views
Standard work-around for using a Solidity constant array (which is not supported) in pure function?
I have an array in my contract like this and a pure method which uses it like this (simplified exmaple because my real exmaple is many more lines):
uint[16] constant x = [10, 2, 6, 42, 19, 5, 4, 36, ...
1
vote
0answers
27 views
Why is an address changing when I add it to an array?
I'm encountering a memory / storage issue (I think) w/ an array of addresses where I want to swap out one address with another.
Here's how I've initialized the array:
address[] public maintainers;
...
1
vote
4answers
706 views
loop to find the highest value in an array
I have made a struct which has an address called playersAddress and a uint called numbers.
I then have a fixed sized array which has in it the playersAddress and the numbers.
When someone calls ...
1
vote
0answers
311 views
passing byte[] to smart contract using nethereum
I made a solidity function that allow a user to send multiple transactions with the same nonce as a singleton Tx signer:
function multipleTransferPreSigned
(
bytes[] _signature,
address[] ...
1
vote
0answers
48 views
Gas cost of adding an item to a class-level (storage) array
I would like to make sure that the gas cost of adding an item to a (storage) array is constant, i.e., not dependent on the length of the array.
To my understanding, the relevant EVM operation is ...
1
vote
0answers
101 views
Understanding Solidity Libraries using Solidity Docs code example
I was going through this code (see code below) about how to use libraries in solidity docs :
https://solidity.readthedocs.io/en/v0.4.24/contracts.html?highlight=library#libraries and there are some ...
1
vote
1answer
28 views
Best ways to get only “active” in arrays - get group members
let's say I have an group contract where users can join and leave groups. When a user joins a group, his address will be added to members[groupId]. When he lefts, the members[groupId] will be set to ...
1
vote
1answer
294 views
solidity sorting array - LIFO / FIFO
I am adding to an bytes32[] array via push().
When I traverse the array with for (uint i = 0; i < array.length; i++), This is First in First Out (FIFO) sequence right?
How can one perform a ...
1
vote
0answers
353 views
Dynamic arrays VS mappings when it comes to gas usage?
I'm puzzled what is more efficient to use, from the point of gas consumption (storage and execution), dynamic array or the mapping and element counter.
To be more clear, I'm not asking the basic data ...
1
vote
0answers
313 views
Mocha timeout, not resolving promise of large array from method.mymethod.call()
I'm trying to test a contract getter method that returns a large array. I am testing using the web3 library in Mocha with ganache-cli provider. My contract deploys alright, but trying to call the ...
1
vote
0answers
92 views
Remix testing timeout with JavaScript VM when calling a large array
I'm trying to test a contract getter method that returns a large array. I am using Remix and deploying using JavaScript VM. My contract deploys alright, but trying to call the getArray() method causes ...
1
vote
0answers
167 views
Modifiers: can I pass an array or specify that not all of them have to pass, but one is enough (OR functionality instead of AND)
Say I want to restrict a function to only authors and editors. And later on, I want to restrict another function to authors and contributors only.
So ideally, I would add a modifier like this:
...
1
vote
3answers
263 views
How do i add to a nested array within a struct
I am unable to add elements to a array within the struct
struct D {
string name;
address key;
}
struct Aone {
string aid;
B[] blist;
D[] dlist;
}
...
1
vote
1answer
96 views
Smart contract returning values as zeros
pragma solidity ^0.4.18;
contract TransManager {
//state variables
// contract owner
address private creator;
uint transCounter;
// File Meta metaData
struct metaData{
uint id;
...
1
vote
0answers
57 views
What's the suggested way to create a 2D array which can be sparse at the beginning and grow dense later?
I can think of two ways:
1) Allocate a 2D array:
uint256 public W = 15;
uint256 public H = 15;
uint256[W][H] public grid;
2) Use mapping:
mapping (uint8) => mapping(uint8 => uint256)) public ...
1
vote
2answers
357 views
Invalid Op Code - passing bytes32 array to a contract method called from another method of another contract
I've been banging my head on this one for some hours, I'd appreciate any help :)
This is a final edit to clearly state the issue: Is there a proper way to pass a bytes32 array to a method on contract ...
1
vote
1answer
102 views
What does State Trie save when pushing into array?
I'm interested/worried about the size of the State Trie over time
Lets suppose I have a contract with two vars:
uint myNumber;
uint[] myArray;
As far as I understand, If I change the value of "...
1
vote
0answers
97 views
Removing Array Element by Copying to Temp Array
I read you can delete an array element like this:
How to delete an element at a certain index in an array?
I was wondering if I can do it this way too:
function playerUnjoins() {
address[] ...
0
votes
0answers
19 views
Error ; Member “push” is not available in address[] memory outside of storage
I am writing a function to generate trail of all address who owned an asset ( assets is a mapping of asset no to owner no to address of owner).
However while making array of address 'listofOwners' I ...
0
votes
0answers
40 views
Gas requirement is infinite for the function
pragma solidity ^0.5.9;
contract kyc2{
bool public isallowed;
// Structure of customer
struct customer{
string custname;
...
0
votes
1answer
9 views
array.push replacing last value instead of adding to the array
I am attempting to keep a log of when a user does certain things but when a new log event is reached the second log is overwritten instead of adding a new one to the array I am unsure as to why when ...
0
votes
1answer
51 views
Deleting an array in storage (>= 0.6.0)
I need to add elements to a resizable myArray and then delete the myArray. I don't know what the length of myArray will be before the loop, and it's not possible to resize a memory array; that leaves ...
0
votes
0answers
11 views
Dynamic two-dimensional array initialisation
I want to initialise a two-dimensional dynamic array.
For a one-dimensional array it looks like that:
function verify(uint[50] memory input){
uint[] memory input_values = new uint[](input.length);
...
0
votes
2answers
70 views
Solidity 0.4.26 check if element already exists in array
How do I make it so this only adds an identifier to the dataArray if it doesn't exist already?
pragma experimental ABIEncoderV2;
contract structWithMapping{
struct Data{
string[] user;
...
0
votes
0answers
19 views
How can I return string array in solidity?
This is my struct:
struct Token {
address tokenAddress;
uint256 minAmount;
bool emergencyUnlock;
TokenStatus status;
string name;
uint256 decimal;
string thumbnailUrl;
}
...
0
votes
1answer
32 views
Ganache Storage
I am trying to push data to an address array within a struct array. There are no errors, however, when I check the storage of the array in my contract in Ganache, it remains empty. Is there something ...
0
votes
2answers
58 views
Arrays copy memory in Solidity
I have this simple code:
function restart() public returns (uint256[] ) {
uint256[] memory result = new uint256[](5);
result[0] = 10;
uint256[] memory result1 = new uint256[](5);
...
0
votes
0answers
14 views
Arrays copy memory in Solidity
I have this simple code:
uint256[] memory result = new uint256[](5);
result[0] = 10;
uint256[] memory result1 = new uint256[](5);
result1 = result;
result1[1] = 20;
return result;
...
0
votes
0answers
31 views
Computing matrix determinant in Solidity
I am trying to write a solidity contract to compute Matrix determinant.
I am following the C++ implementation from here:
https://www.tutorialspoint.com/cplusplus-program-to-compute-determinant-of-a-...
0
votes
1answer
21 views
Mapping multiple structs to a struct and call them
I have a question about how I should design my contract to achieve the following: I want to create products identifiers (can be struct or string) something like: "product#123abc". Then I want to map a ...
0
votes
1answer
22 views
Can you have an array of mappings? The mappings have an address key and a struct value
Can you have an array of mappings?
I want to have mappings with addresses as keys and structs as the value.
I want to store these addresses in an array and iterate through them.
so far it looks like ...
0
votes
0answers
122 views
Web3- Array returned from function is always empty
I have contract in solidity and I like to return array or array by index.
I'm using experimental feature on, and in remix in solidity I don't have issue with returing the array, but when I use web3 ...
0
votes
0answers
15 views
loop into an array and extract infos for specific address
I'm new in solidity . I'm trying to make a smartContract as bellow
pragma solidity ^0.4.18;
pragma experimental ABIEncoderV2;
contract AnalyseContract {
//struct => new type of data for this ...
0
votes
0answers
22 views
What is an efficient way for converting 'bytes4' into 'bytes' or 'byte[4]'?
I am currently converting bytes4 into bytes like this:
function convert(bytes4 x) public {
bytes memory y = abi.encodeWithSelector(x);
...
}
Is there a more efficient way?
Also, is there an ...
0
votes
1answer
25 views
How can I distribute funds to present stakers efficiently?
I am building a smart contract which keep the token holder's eths for a while and give them rewards when they withdraw. The reward is given from the ethers collected by early withdraw of people. If ...
0
votes
2answers
386 views
Solidity & truffle: get elements from strings array
i'm glad to follow this forum, it is very helpful.
I'm using truffle to develop contracts and i just found that dynamic arrays are not yet suported, for that reason i was using string arrays with a ...
0
votes
0answers
98 views
How to pass the whole array from one contract to another when working with different solidity files?
For example, I am taking one function function transferAddresses() in my contract contract one{} from where I am taking number of addresses in array. Now I want to transfer the whole data of the array ...
0
votes
2answers
153 views
Remove array specific value
In a array that the values are never repeated. Is there a function/library or something similar that you give the value to remove. And the function the empty space in the array??
function remove(uint ...
