link#

✅ Summary#

Method	Moves?	Mutable?	Recommended
`+`	yes	no	sometimes
`format!`	no	no	⭐ best
`push_str`	no	yes	⭐ best for struct
`push`	no	yes	char only
`concat()`	no	no	slice
`join()`	no	no	slice with separator

There are several ways to concatenate strings#

In Rust, there are several ways to concatenate strings, and each one works a little differently because of ownership rules.
Here are the main ways with clear examples.

1. Using `+` operator (moves left side)#

fn main() {
    let a = String::from("young");
    let b = String::from("ha");

    let c = a + &b;

    println!("{c}");
}

Output

youngha

IMPORTANT
a is moved

let c = a + &b;

is actually:

String::add(a, &b)

So after this, a cannot be used.

2. Using `format!` (safe, no move)#

Best general method.

fn main() {
    let a = String::from("young");
    let b = String::from("ha");

    let c = format!("{}{}", a, b);

    println!("{c}");
    println!("{a}");
    println!("{b}");
}

Output

youngha
young
ha

✔ does not move
✔ easiest
✔ recommended

3. Using `push_str` (modify existing string)#

Best when mutating struct / variable.

fn main() {
    let mut a = String::from("young");

    a.push_str("ha");

    println!("{a}");
}

Output

youngha

4. Using `push` (single char)#

fn main() {
    let mut a = String::from("young");

    a.push('!');

    println!("{a}");
}

Output

young!

5. Using `concat()` (slice of strings)#

fn main() {
    let a = "young";
    let b = "ha";
    let c = "kim";

    let s = [a, b, c].concat();

    println!("{s}");
}

Output

younghakim

6. Using `join()`#

fn main() {
    let parts = ["young", "ha", "kim"];

    let s = parts.join("-");

    println!("{s}");
}

Output

young-ha-kim

link#

✅ Summary#

There are several ways to concatenate strings#

1. Using + operator (moves left side)#

2. Using format! (safe, no move)#

3. Using push_str (modify existing string)#

4. Using push (single char)#

5. Using concat() (slice of strings)#

6. Using join()#

1. Using `+` operator (moves left side)#

2. Using `format!` (safe, no move)#

3. Using `push_str` (modify existing string)#

4. Using `push` (single char)#

5. Using `concat()` (slice of strings)#

6. Using `join()`#