What is address[]?

Question

What is address[] in solidity?

I found it in a tutorial video I watched but I am unable to find any information about this on internet! Does anyone knows?

Answer 1

address[] is a type, an array of addresses. You can think of it as a list of addresses.

The square brackets, [], are use to specify that this type is an array.

You can create an array of many things, like an array of uint256 numbers:

uint256[] numbers;

And many more with a similar syntax.

Many languages use the [] to create or declare an array. Like Javascript: const numbers = [];. We can usually initiate an array with values, like in js: const numbers = [1,2,3,4,5];. In Solidity it would look like this for an array of uint256 numbers in storage: uint256[] numbers = [1,2,3,4];

In your case, an array of addresses can be declared as a state variable as follows:

address[] admins;

And then, in another function you can add addresses to that array:

function addAdmin(address adminAddress) public onlyOwner {
   admins.push(adminAddress);
}

Of if you know the address before hand you can hard code them while you declare the array of addresses, like this:

address[] admins = [0x66B0b1d2930059407DcC30F1A2305435fc37315E, 0x6827b8f6cc60497d9bf5210d602C0EcaFDF7C405];

Arrays are really useful to hold a collection of things, objects, numbers, addresses, strings, etc.

We access arrays by index, starting at index 0 for the first element in most programming languages. If I want to access the first element of the array, then I do:

admins[0];

For the second:

admins[1];

And so on. Or in a loop:

for(uint256 i = 0; i < admins.length; i++) {
  address adminAddress = admins[i];
  // ...
  // do something with adminAddress
}

And so on.

Solidity has many rules for arrays. State and local arrays are usually declared differently and used a bit differently in some cases. To learn more about them you can check the documentation: https://docs.soliditylang.org/en/latest/types.html#arrays

I hope it has helped.

Answer 2

In Solidity, address[] is an array consisting of addresses.

See: How can I instantiate an array of addresses?

Answer 3

In Solidity, address[] is an array of type address. An address in Solidity is a data type that represents a 20-byte Ethereum address. Arrays in Solidity are a type of data structure that allows you to store and manage a collection of data. In this case, an address[] array would be used to store a collection of Ethereum addresses.