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Questions tagged [arrays]

Questions regarding the use of Arrays in solidity.

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1answer
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Pushing a stuct into an array

What i am attempting to do is elementary, adding a struct to a storage array. But for some reason I am getting the following error TypeError: Indexed expression has to be a type, mapping or array (...
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1answer
25 views

Transaction pending

If I call this function the transaction get pending and never finish. Any idea? pragma solidity ^0.4.24; contract test { uint[] values = [1,2,3,4,5,6]; function removeValueFromArray(uint _num) ...
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0answers
27 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 ...
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1answer
17 views

How to set token holder's address without duplication?

In following code I've implemented two functions to set and get Token holders. function setTokenHolders(address _to)internal returns(bool){ for(uint i = 0; i<= tokenHolders.length; i++){ ...
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1answer
23 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 ...
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1answer
24 views

Store different numbers in Blockchain

pragma solidity ^0.4.24; contract Count { uint256 storeddata; function set(uint256 x) public { storeddata = x; } function get() public view returns(uint256) { return ...
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1answer
26 views

Solidity : Error when pushing an address into a dynamic address type array

I'm trying to insert an address into an address type dynamic array. It works well when I do the operation inside a function. There are no errors and the elements are properly pushed into the array. ...
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0answers
23 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, ...
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1answer
14 views

Problem with array of adresses

I have following code of my smart contract, it has simple problem: browser/Referrals.sol:100:35: TypeError: Type function (uint256) pure returns (address[] memory) is not implicitly convertible ...
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1answer
22 views

Index 0 in empty address array reverts

I have a struct that has an array of addresses. When the address array is empty and I try to get index 0 I would expect it to return address(0), but instead it reverts. Any way around this? struct ...
0
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1answer
26 views

How Ethereum stores its data in the blockchain [duplicate]

I am new to ethereum and the blockchain, but I am wondering about blockchain databases. Mainly I am wondering how exactly the database data and the blockchain merge. For instance, in a database you ...
0
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1answer
35 views

How to Serialize/Deserialize array of bytes?

I'm writing a smart contract and inevitably need to have arrays of bytes as input and output of functions. In remix arrays work just fine but with web3j and web3js there are several issues with arrays ...
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1answer
14 views

Struct and Mapping input value error of Invalid Opcode while calling setSeller() to store multiple seller's addresses

What dose the -1 means? Or why we should use -1 while pushing one element in array. What should I enter in sellerAccounts: field as input? pragma solidity ^0.5.1; contract Seller{ struct ...
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1answer
102 views

Solidity 0.5.x - make address array payable

I'm trying to write a contract that uses an address[] array which should contain payable addresses. But apparently creating a payable address array doesn't work in solidity 0.5.x. All I'm trying to ...
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2answers
111 views

Return the struct inside array inside array

pragma solidity >= 0.4.25 < 0.6; contract Bank { struct Customer { uint age; } Customer[][] customers; function foo() public { if (customers.length > 0) { ...
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1answer
24 views

Array of struct inside and a array

It´s posible to save structs inside array and all this array´s inside the same array. I mean: [ [{"struct"}, {"struct"}, {"struct"}], [ {"struct"}, {"struct"}], [{"struct"}, {"struct"}, {"struct"}, {"...
3
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1answer
29 views

Why is multidimensional array declaration order reversed?

Why is multidimensional array declaration order reversed? As an example, an array of 5 dynamic arrays of uint is uint[][5] (note that the notation is reversed when compared to some other ...
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2answers
136 views

Unable to return address array in solidity

I have the following code for a simple gambling game. The code works fine except for getPlayers function pragma solidity >=0.4.22 <0.6.0; contract Lottery { address payable public manager; ...
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0answers
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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; ...
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1answer
36 views

How do I take value from array of objects?

I have a problem with my code. contract Registration { address public owner; uint conceptPrice; uint conceptValue; function Registration(uint _conceptPrice) public { owner = msg.sender; ...
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1answer
40 views

Problem with push

This is my code. When i push address into participants the length is zero. Why? pragma solidity ^0.4.0 contract Registration { address public owner; uint threshold = 2; address [] ...
2
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1answer
51 views

How to properly delete the first element in an array?

Is it possible to delete the first element of an array without shifting all elements later? My guess is that I can remember the index of the 'current first element', like so: uint[] public myArray; ...
2
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2answers
65 views

How do I read an array inside of a struct?

as part of learning solidity and smart-contract development, I am developing a simple part management/tracking system. I have a struct and a mapping for a list of parts as such: struct Part { uint ...
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3answers
27 views

Is There any way to check if the entered key is having a corresponding value in a mapping or not?

Suppose In a banking system many people are enrolled (managed through mapping ) mapping (address => bool) enrolled; And only those can deposit who are enrolled in the bank. Can I check if ...
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4answers
101 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 ...
2
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1answer
119 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 ...
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2answers
42 views

How can I build this list of addresses

An investment round ask new investors to put exactly 0.1 ether to enter the round. function invest() public payable { require(msg.value == 0.1 ether); } How can I save every new investor ...
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2answers
105 views

Efficient way of checking and inserting array address that is unqiue

I have a following requirement that need to be cater in dapp. Insert array of address The array need to be unique. If one of the array address already exists, reject and revert entire operation. ...
0
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1answer
38 views

Return an array of mappings reflecting global state between struct associations?

I am looking for a construct that's something like "return an list of key value pairs," which I think would be implemented as an array of mappings. Is that right? That is, I'd like a data structure ...
3
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1answer
44 views

Bytes variables are connected

Why are these variables confounding? The returned result shows that both loops are effecting both bytes variables (second returns the same result). function mix() public returns (bytes) { ...
0
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1answer
147 views

Array.push not working

I am new here and I am suffering with the case below, I am trying to push data into an Array, but I can't make it work, the array continuous with zero length. contract StarNotary is ERC721 { ...
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2answers
58 views

Remove an element in array but the struct is still inside

I have this array of struct struct Prodotto { string titolo; address owner_address; } Prodotto[] public prodotti; And I create two products like this: titolo: titolo stravolto owner: ...
0
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1answer
14 views

Should I maintain an array of all the valid keys in a given mapping?

I have a contract which maintains a map of valid wallets. In this map, the keys are wallet addresses and the values are wallet parameters: struct WalletParams { bool valid; uint x; uint ...
0
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1answer
47 views

Mapping address to multidimensional uint

I'm trying to create an array contains addresses which belongs to particular transaction ID. Array structure: transactions[0x12345][0] = 123456 transactions[0x12345][1] = 789101 transactions[0x12345]...
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1answer
38 views

Why is delete on arrays implemented in an energy and gas wasting way?

If I delete the whole array (static/dynamic), then all elements of an array are set to default value. So, it means that if an array has a million elements, then I have to pay gas for setting up of ...
2
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0answers
51 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 ...
0
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1answer
19 views

Read List of Posts using struct

I tried to read a list of posts using the code below struct posts { bytes32 postTag; string post; address[] acceptedBy; uint8[] voteCount; } mapping(address => posts) totaluserPosts; ...
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2answers
55 views

Display Array of struct within array of struct in react

I'm trying to create 2d array of different types, one of the users have suggested to use struct within a struct method -> 2d array of different types? Now I run into problem how to display it in my ...
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2answers
44 views

initialise array of struct inside a new struct

Following up on the question of 2d array of different types: 2d array of different types? How would one go about initializing a new array of structs (Vote) when creating a new struct (Project) ...
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1answer
36 views

2d array of different types?

I got quite an interesting question. I have created an array of structs, and in each struct, I have an array of address. Then I got a method that when its called on given struct [index] its adds ...
0
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2answers
103 views

Solidity: How to initialize an array within a struct, passed as a parameter?

pragma solidity 0.4.25; contract A{ struct N{ string any; uint256[] numberArray; } N[] public numbers; function init(uint256[] _numbers) public{ for (uint256 ...
0
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1answer
82 views

Why is there a difference between a public array and a function which returns it?

On-chain example: pragma solidity 0.4.24; contract MyContract { uint[] public array; constructor() public { array.push(1); array.push(2); array.push(3); } ...
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0answers
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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[] ...
0
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1answer
732 views

How to loop through a array of addresses?

I have a mapping and an array that contains a list of addresses of students. When I loop over that array, the method .length is not working. How can I loop through the array Student_list shown below?...
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3answers
296 views

How to map an address with a string array in solidity?

Goal: I wish to store an array of names with an address in a smart contract. It's more like Key-Value pairs where addresses are paired with a list of type strings. Can I use mapping to implement this?...
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0answers
23 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
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1answer
78 views

Changing dynamic array index content

I'm trying to to make a contract which lets the user choose any number he likes to populate an array of integers used in a mapping. Then he can choose any index of this array to increase its value by ...
2
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1answer
26 views

Array of items vs mapping+array of ids with web3js?

In most articles they recommend to use mapping. But mappings don't allow to iterate their items directly. And nobody says what to do if you need to get all the stored items. In my case I need store ...
2
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1answer
44 views

Can i create a new address this way?

I am busy with a project. So I have an array of a struct within another struct. In this case for example array of CattleHealth in Cattle. In my RecordHealth function, I am taking the address of the ...
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1answer
28 views

How to add an instance of a struct to an array of another?

Hi I am pretty new to solidity. I am busy with a project that records all kinds of information about cattle. In my code below my cattle struct has an array of CattleHealth and CattleGrowth which are ...