for-loops

Table of Contents📚

• What is a for loop❓
• The for keyword🔑
• Vector iteration
  • What is a vector❓
  • Declaring a vector
  • Iterating over a vector
  • Iterating over a vector with index🔢

For loops🔢

What is a for loop❓

For loops are used to iterate over a given sequence.

The for keyword🔑

The for keyword is used to create a for loop.

Example:

for count in 0..5 {
    println!("🔢 -> {}", count);
}

Here, count is the variable that holds the current value of the loop, and 0..5 is an expression that generates the range of values to iterate over.

0..5 is the range of values from 0 to 5 (5 not included).

Output:

🔢 -> 0
🔢 -> 1
🔢 -> 2
🔢 -> 3
🔢 -> 4

It is possible to store a range in a variable:

let range = 0..5;
for count in range {
    println!("📢 {}", count);
}

Output:

📢 0
📢 1
📢 2
📢 3
📢 4

Vector iteration

What is a vector❓

A vector is a group of values that can be iterated over.

Declaring a vector

A vector can be declared with the vec! macro and the values separated by commas.

Example:

let animals = vec!["🐒 Monkey", "🐕 Dog", "🦄 Unicorn"];

Iterating over a vector

A vector can be iterated over using the for loop.

Example:

let animals = vec!["🐒 Monkey", "🐕 Dog", "🦄 Unicorn"];

for animal in animals.iter() {
    println!("My 💫 favorite animal 💫 is the {}", animal);
}

Output:

My 💫 favorite animal 💫 is the 🐒 Monkey
My 💫 favorite animal 💫 is the 🐕 Dog
My 💫 favorite animal 💫 is the 🦄 Unicorn

ℹ️ We use the iter() method to get an iterator over the vector and to prevent the ownership of the vector from being moved and being able to use it after the loop

Iterating over a vector with index🔢

It is possible to iterate over a vector knowing the index of the current element.

We can do that with the enumerate() method.

Example:

let fruits = vec!["🍇 Grapes", "🍈 Melons", "🍌 Bananas"];

for (index, fruit) in fruits.iter().enumerate() {
    println!("I love {} at index {}", fruit, index);
}

Output:

I love 🍇 Grapes at index 0 
I love 🍈 Melons at index 1
I love 🍌 Bananas at index 2

ℹ️ We use (index, number) because the enumerate() method returns a tuple with the index and the value.

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Course created by SkwalExe and inspired by Dcode