for loop
- Rust course
- Beginner
- Lesson 40/115
- 4 min
Iterate over an iterator with for.
The for loop
for yields every element of an iterator in turn; it is the most common loop in Rust. Ranges: 0..5 (excluding 5), 1..=5 (including 5):
for i in 1..=3 {
print!("{i} ");
}
for meyve in ["elma", "armut"] {
println!("{meyve}");
}
for i in (1..=3).rev() { // 3 2 1
print!("{i} ");
}Index and value
To get the position together with the element, enumerate is used; step_by skips steps:
let isimler = ["Ada", "Can", "Ece"];
for (i, ad) in isimler.iter().enumerate() {
println!("{}. {}", i + 1, ad);
}
for n in (0..=10).step_by(5) { // 0 5 10
print!("{n} ");
}Practice Numbered list
Walk the array let gorevler = ["kod yaz", "test et", "yayınla"]; with .iter().enumerate() and print each line as 1. kod yaz.
Starter code
fn main() {
// buraya yaz
}Sample solution
fn main() {
let gorevler = ["kod yaz", "test et", "yayınla"];
for (i, g) in gorevler.iter().enumerate() {
println!("{}. {}", i + 1, g);
}
}Expected output
1. kod yaz 2. test et 3. yayınla
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which values does <code>for i in 0..3</code> give?
- 3, 2, 1
- 0, 1, 2 Correct answer
- 0, 1, 2, 3
- 1, 2, 3
Explanation: .. excludes the end; to include it, ..= is used.
2 Inclusive range
Question
for i in 1____10 {
toplam += i;
} // 1'den 10'a (dahil)
Answer
for i in 1..=10 {
toplam += i;
} // 1'den 10'a (dahil)Explanation: ..= includes the end of the range too.
3 Expression and values
| Term | Meaning |
|---|---|
0..3 |
0 1 2 |
1..=3 |
1 2 3 |
(1..=3).rev() |
3 2 1 |
(0..=10).step_by(5) |
0 5 10 |