Rust For Loop
The for Loop
When you know exactly how many times you want to loop through a block of code, use the for loop together with the in keyword, instead of a while loop:
This prints numbers from 1 to 5.
Note: 1..6 means from 1 up to (but not including) 6.
Note: Rust handles the counter variable (i) automatically,
unlike many other programming languages. You
don't need to declare or increment it manually.
Inclusive Range
If you want to include the last number, use ..= (two dots and an equals sign):
This prints numbers from 1 to 6, including 6.
Break and Continue
Just like other loops, you can use break to stop the loop and continue to skip a value:
Example
for i in 1..=10 {
if i == 3 {
continue; // skip 3
}
if i == 5 {
break; // stop before printing 5
}
println!("i is: {}", i);
}
Try it Yourself »
This prints 1, 2, and 4. It skips 3 and stops before 5.
Rust Loops Summary
Rust has three types of loops that let you run code over and over again. Each one is used in different situations:
1. loop
The simplest kind of loop. It runs forever unless you stop it with break.
loop {
// do something
if condition {
break;
}
}
Use loop when you don't know in advance how many times to repeat.
2. while
Repeats code while a condition is true. It checks the condition before each loop.
while count <= 5 {
println!("{}", count);
count += 1;
}
Use while when you want to repeat code until something happens.
3. for
Repeats code a fixed number of times.
for i in 1..=5 {
println!("{}", i);
}
Use for when you know exactly what to loop through.
Extra Keywords
You can use these in any loop:
break- stop the loopcontinue- skip a value in the loop
Now that you know how loops work, you are ready to start working with functions and reusable code!
