Working with Strings in Move

In this tutorial, we will learn how to work with strings in the Move programming language. Move does not have a native type for strings, but it provides a convenient wrapper for handling strings using the std::string::{Self, String} module.

1. Create a Move module with a struct:

Create a new Move file (e.g., "strings_example.move") and define a module called "strings" with a struct named "Name":

module examples::strings {
    use sui::object::{Self, UID};
    use sui::tx_context::TxContext;
    use std::string::{Self, String};
 
    struct Name has key, store {
        id: UID,
 
        /// Here it is - the String type
        name: String
    }
}

2. Import the String type:

To use the String type, import it from the std::string module:

use std::string::{Self, String};

3. Define a function to create a Name object:

Add a public function called issue_name_nft that takes a vector<u8> (representing raw bytes of a string) and a mutable transaction context as input. This function will create and return a Name object:

public fun issue_name_nft(
    name_bytes: vector<u8>, ctx: &mut TxContext
): Name {
    // Your code here
}

4. Implement the function to create a Name object:

Inside the issue_name_nft function, create a Name object by initializing its id and name fields. Convert the raw bytes (name_bytes) into a String type using the string::utf8 function:

public fun issue_name_nft(
    name_bytes: vector<u8>, ctx: &mut TxContext
): Name {
    Name {
        id: object::new(ctx),
        name: string::utf8(name_bytes)
    }
}

5. Final Move module with String handling:

After implementing the function, your complete "strings_example.move" module should look like this:

module examples::strings {
    use sui::object::{Self, UID};
    use sui::tx_context::TxContext;
    use std::string::{Self, String};
 
    struct Name has key, store {
        id: UID,
 
        /// Here it is - the String type
        name: String
    }
 
    /// Create a name Object by passing raw bytes
    public fun issue_name_nft(
        name_bytes: vector<u8>, ctx: &mut TxContext
    ): Name {
        Name {
            id: object::new(ctx),
            name: string::utf8(name_bytes)
        }
    }
}

Save the file, and you've successfully implemented string handling in a Move module using the std::string::{Self, String} module.