while let ๋ฐ˜๋ณต๋ฌธ

๋งˆ์ง€๋ง‰์œผ๋กœ, ๋ฌดํ•œ ๋ฃจํ”„๋ฅผ ๋งŒ๋“œ๋Š” loop ํ‚ค์›Œ๋“œ๊ฐ€ ์žˆ์Šต๋‹ˆ๋‹ค:

fn main() {
    let v = vec![10, 20, 30];
    let mut iter = v.into_iter();

    while let Some(x) = iter.next() {
        println!("x: {x}");
    }
}

v.into_iter()๊ฐ€ ๋ฐ˜ํ™˜ํ•œ ๋ฐ˜๋ณต์ž๋Š” next()๊ฐ€ ํ˜ธ์ถœ๋  ๋•Œ๋งˆ๋‹ค Option<i32>๋ฅผ ๋ฐ˜ํ™˜ํ•ฉ๋‹ˆ๋‹ค. ๋ฐ˜๋ณต์ž๊ฐ€ ์™„๋ฃŒ๋  ๋•Œ๊นŒ์ง€๋Š” Some(x)๋ฅผ ๋ฐ˜ํ™˜ํ•˜๊ณ  ๋งˆ์ง€๋ง‰์—” None์„ ๋ฐ˜ํ™˜ํ•ฉ๋‹ˆ๋‹ค. while let์„ ํ†ตํ•ด ๋ฐ˜๋ณต์ž์˜ ๋ชจ๋“  ์•„์ดํ…œ์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค.

ํŒจํ„ด์— ๊ด€ํ•œ ์„ค๋ช…์€ ํŒจํ„ด ๋งค์นญ์„ ์ฐธ์กฐํ•˜์„ธ์š”.

  • while let์€ ๊ฐ’์ด ํŒจํ„ด์— ๋งค์น˜๋˜๋Š” ๋™์•ˆ ๊ณ„์†๋ฉ๋‹ˆ๋‹ค.
  • while let ๋ฃจํ”„ ๋Œ€์‹  ๋ฌดํ•œ ๋ฃจํ”„๋ฅผ ์‚ฌ์šฉํ•˜๊ณ  iter.next()๊ฐ€ ๋นˆ ๊ฐ’์„ ๋ฐ˜ํ™˜ํ•  ๋•Œ ๋ฃจํ”„๋ฅผ ๋น ์ ธ๋‚˜์˜ค๋„๋ก ์ž‘์„ฑํ• ์ˆ˜๋„ ์žˆ์Šต๋‹ˆ๋‹ค. while let์€ ๊ทธ๋Ÿฌํ•œ ๊ฒฝ์šฐ๋ฅผ ์œ„ํ•œ ๋ฌธ๋ฒ•์  ํŽธ์˜๋ฅผ ์ œ๊ณตํ•ฉ๋‹ˆ๋‹ค.