Rust by Example: Strings

In Rust there are two main types of strings: string slices (&str) and the String type. String slices are references to some UTF-8 encoded string data stored elsewhere. The String type, on the other hand, is allocated on the heap and is therefore able to store an amount of text that is unknown to us at compile time.
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fn main() {

String slice is an immutable reference to a UTF-8 encoded string in memory that is not owned by the program. String slices are written as &str.

 
    let s = "hello, world!";
    let first_word = &s[0..5];
    let second_word = &s[7..12];
    println!("{} {}", first_word, second_word);

String literal, fixed size and immutable string slice, and are stored in the program's binary as immutable data. Therefore, string literals are considered string slices (&str).

 
    let literal: &str = "hello, world!";
    println!("{}", literal);

String type, a mutable UTF-8 encoded string allocated on the heap, and can dynamically grow and shrink during runtime.

 
    let str_from: String = String::from("hello, world!");
    println!("{}", str_from);

Create String type with new()

 
    let mut str_new: String = String::new();
    str_new.push_str("hello, world!");
    println!("{}", str_new);

Create String type with format! (docs)

 
    let world: &str = "world!";
    let str_format: String = format!("hello, {}", world);
    println!("{}", str_format);

Create String type with to_string()

 
    let str_to_str: String = "hello, world!".to_string();
    println!("{}", str_to_str);
}

$ rustc strings.rs
$ ./strings
hello world
hello, world!
hello, world!
hello, world!
hello, world!
hello, world!
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