Confused with the Pure Function

[MrMandu7]

Patrick said Pure Function doesn't modify or read the blockchain. So what is it actually used for?

[alwayscommit]

This short guide would be helpful
https://www.educative.io/edpresso/what-are-pure-functions-in-solidity

[alymurtazamemon]

@MrMandu7
View and Pure are only used to read the data from the blockchain and because they both read the data and do not perform any computation on the blockchain that's why both do not consume gas and are gas-free.

Now understand when we use View and when we use Pure.

Every smart contract has variables that we say state/storage variables, now when we read those state variables inside the function, we have to mark our function as View.

Let's say you create

contract AnyName {
uint256 num = 10;

  function read() external view returns(uint256) {
    return num;
  }
}

As you can see here, I read the num state variable so in that case, I have to use view, I cannot use pure here.

On the other hand, if we only read data from our function, let's say a function that returns "Hello world", in that case, we are not reading any state variable so we can mark our function as pure.

Hope it clears your query if not then please ask again and I will try to clear it with a more clean example.

Thank you
Ali Murtaza

[crypte-1]

here is my take on it

Pure and view functions are special functions in solidity

1. Pure function : Does not modify values of state variables and not even read state variable values
2. View function : Does not modify values of state variables , But reads state variables

pure and view functions both are free if the call was from outside of the blockchain

[PatrickAlphaC]

I like this a lot

[mattjaf]

You can use pure functions to do computations that do not modify the state variables,

such as converting a SVG to image URI