A for loop is a special type of loop in Rust which allows us to loop over the items of a collection, such as a string or an array.
Looping through a string:
For example, a string is a sequence of characters, so we can use a for loop to iterate over each character and do something with that character:
let name = "Andy";
for letter in name.chars() {
println!("{}", letter);
}
Let's break down this code:
- The
forkeyword that indicates the start of aforloop. letteris the loop variable. It will take the value of each different item in the collection- The
inkeyword separates the loop variable from the collection we will iterate on name.chars()is the collection to loop over
The output of this code is:
A
n
d
y
As you can see, on each iteration, letter was assigned the value of the next item in the string and inside the loop, we printed that value.
Looping through an array:
We can also use for loops with lists:
let fruits = vec!["banana", "orange", "pear", "kivi"];
for fruit in &fruits {
println!("I eat {}", fruit);
}
The output of this code is:
I eat banana
I eat orange
I eat pear
I eat kivi
Assignment
Now let's greet our friends using a for loop!
Hint
Look at the examples above if you get stuck.
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