StringsBasics.md

Introduction to Strings

The Movement blockchain provides a powerful and efficient module for working with strings, designed to handle text data in decentralized applications. This README details the available functions and best practices for utilizing the string module effectively.

Importing the String Module

To use the string module, include it in your module or script with the following import statement:

use std::string;

Key Functions in the String Module

1. String Concatenation

Concatenate strings by appending one to another using the string::append function. Note that append requires a mutable reference to the target string::String.

Example

fun append_to_string(mut str1: &mut string::String, str2: string::String) {
    string::append(&mut str1, str2);
}

2. String Length

Determine the number of characters in a string using string::length. This function takes an immutable reference to a string::String.

Example

fun get_string_length(input: &string::String): u64 {
    string::length(input)
}

3. Substring Extraction

Extract a substring from a string using string::sub_string. This function also requires an immutable reference to a string::String.

Example

fun extract_substring(input: &string::String, start: u64, length: u64): string::String {
    string::sub_string(input, start, length)
}

4. UTF-8 Conversion

Convert a vector<u8> to a string::String using the string::utf8 function.

Example

fun utf8_to_string(input: vector<u8>): string::String {
    string::utf8(input)
}

5. Bytes Conversion

Convert a string::String back to a vector<u8> using the string::bytes function.

Example

fun string_to_bytes(input: &string::String): vector<u8> {
    *string::bytes(input)
}

6. To String Conversion

Convert various types into a string::String representation using the aptos_std::string_utils::to_string function.

Example

use aptos_std::string_utils;
use std::string;

fun convert_to_string(value: u64): string::String {
    string_utils::to_string(value)
}

Best Practices

1. Validation: Ensure strings meet expected formats before performing operations.
2. Efficiency: Minimize unnecessary string operations to optimize performance.
3. Error Handling: Handle cases where functions like sub_string may fail gracefully.

Summary

The string module in the Movement blockchain provides essential tools for text manipulation and validation. By leveraging its functions effectively, developers can build robust smart contracts with advanced string-processing capabilities.

Resources

• String Module Source Code
• String Utils Source Code