Is there a method like JavaScript's substr in Rust?

Question

I looked at the Rust docs for String but I can't find a way to extract a substring.

Is there a method like JavaScript's substr in Rust? If not, how would you implement it?

str.substr(start[, length])

The closest is probably slice_unchecked but it uses byte offsets instead of character indexes and is marked unsafe.

Answer 1

For characters, you can use s.chars().skip(pos).take(len):

fn main() {
    let s = "Hello, world!";
    let ss: String = s.chars().skip(7).take(5).collect();
    println!("{}", ss);
}

Beware of the definition of Unicode characters though.

For bytes, you can use the slice syntax:

fn main() {
    let s = b"Hello, world!";
    let ss = &s[7..12];
    println!("{:?}", ss);
}