some type convert

Rust type.md

Converting a &str to a String

There are several ways to convert.

• to_string()

fn main() {
    let new_string = "hello".to_string();
}

to_string() turns a &str to String.

• to_owned()

fn main() {
    let new_string = "hello".to_owned();
}

&str is an immutable reference to a String, use to_owned() turns it into a String you own and can do things with.

• String::from()

fn main() {
    let new_string = String::from("hello");
}

• String::push_str()

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

• format!()

fn main() {
    let world_var = "world";
    let new_string = format!("hello {}", world_var);
}

use the macro to format some more complex formatting with &str as input.

• into()

fn main() {
    let new_string = "hello".into();
}

This is a simple conversion if you don't care about the ambiguity.

Converting String to &str

• &String types turn into &str if the method call needs it
• let my_str: &str = &my_string, if you want to explicitly specify a &str type