String concatenation

Recipe	Crates	Categories
Compare string concatenation methods

Concatenate strings

fn concatenate_with_plus() {
    let a = String::from("hello");
    let b = " ";
    let c = String::from("world");
    let result: String = a + b + &c;
    // Note that `a` is moved here and can no longer be used
    println!("{}", result);
}

fn concatenate_with_format() {
    let a = String::from("hello");
    let b = String::from("world");
    let result: String = format!("{} {}", a, b); // or format!("{a} {b}");
    println!("{}", result);
}

fn concatenate_with_push_str() {
    let mut a = String::from("hello");
    let b = " ";
    let c = "world";
    a.push_str(b);
    a.push_str(c);
    println!("{}", a);
}

fn concatenate_with_join() {
    let words = ["hello", "world"];
    let result: String = words.join(" ");
    println!("{}", result);
}

fn concatenate_with_concat_macro() {
    let result: &str = concat!("hello", " ", "world");
    println!("{}", result);
}

fn concatenate_with_concat() {
    let result: String = ["hello", " ", "world"].concat();
    println!("{}", result);
}

use concat_string::concat_string;

// The `concat_string!` macro concatenates string slices into owned strings.
// concat_string! accepts any number of arguments that implement AsRef<str>
// and creates a String with the appropriate capacity.
fn concatenate_with_concat_string() {
    println!("{}", concat_string!("Hello", String::from(" "), "world"));
}

fn concatenate_with_push() {
    let mut a = String::from("hello");
    let b = ' ';
    let c = 'w';
    // Appends the given `char` to the end of the `String`.
    a.push(b);
    a.push(c);
    println!("{}", a);
}

#[allow(clippy::string_extend_chars)]
fn concatenate_with_extend() {
    let mut a = String::from("hello");
    let b = " world";
    a.extend(b.chars());
    println!("{}", a);
}

fn concatenate_with_collect() {
    let words = ["hello", " ", "world"];
    let result: String = words.into_iter().collect();
    println!("{}", result);
}

fn concatenate_with_collect_iter() {
    let words = ["hello", " world"];
    let result: String = words.iter().copied().collect();
    println!("{}", result);
}

use joinery::JoinableIterator;

fn concatenate_with_joinery() {
    let words = ["hello", "world"];

    // Join the words with a space separator
    let result = words.iter().join_with(" ").to_string();

    println!("{}", result);
}

use std::fmt::Write;

fn concatenate_with_write_macro() {
    let part1 = "hello";
    let part2 = " world";
    let mut result = String::new();
    write!(&mut result, "{} {}", part1, part2).unwrap();
    println!("{}", result);
}

fn concatenate_with_chain() {
    let part1 = "hello";
    let part2 = " world";
    let result: String = part1.chars().chain(part2.chars()).collect();
    println!("{}", result);
}

fn main() {
    concatenate_with_plus();
    concatenate_with_format();
    concatenate_with_push_str();
    concatenate_with_join();
    concatenate_with_concat_macro();
    concatenate_with_concat();
    concatenate_with_concat_string();
    concatenate_with_push();
    concatenate_with_extend();
    concatenate_with_collect();
    concatenate_with_collect_iter();
    concatenate_with_joinery();
    concatenate_with_write_macro();
    concatenate_with_chain();
}

String concatenation benchmark⮳