Day 6: Loops – Time Warp 🔄

Welcome to Loop Central, where we learn to automate repetitive tasks like a pro. Imagine being able to "time travel" through an array of anime characters with just a few lines of code. Loops let you do just that! In this session, you'll understand the three core loops in JavaScript:

• for loop

• while loop

• do-while loop

By the end, you’ll know how to loop through any data like a true anime sensei.

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Why Loops?

Instead of writing repetitive code, loops help you automate actions by repeatedly executing a block of code until a condition is no longer true. This can be useful for:

• Printing lists (like favorite anime characters).

• Iterating over arrays.

• Automating tasks like countdowns, animations, and more.

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Loop Types: Explained

1. for Loop: The Classic Binge-Watcher

Use this loop when you know exactly how many times you want to iterate (like watching 12 episodes of a series).

javascriptCopy codeconst animeCharacters = ['Goku', 'Naruto', 'Luffy', 'Eren', 'Tanjiro'];

// Loop through the array using a for loop
for (let i = 0; i < animeCharacters.length; i++) {
  console.log(`${i + 1}. ${animeCharacters[i]}`);
}

Output:

markdownCopy code1. Goku  
2. Naruto  
3. Luffy  
4. Eren  
5. Tanjiro

• How it works:

  1. let i = 0: Start at index 0 (first character).

  2. i < animeCharacters.length: Keep looping as long as i is less than the length of the array.

  3. i++: Increment i after each iteration.

Pro Tip:

Use reverse loops to print the characters in reverse order:

javascriptCopy codefor (let i = animeCharacters.length - 1; i >= 0; i--) {
  console.log(`${animeCharacters[i]}`);
}

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2. while Loop: The Determined Dreamer

The while loop is like Naruto—he keeps running until his goal is achieved! Use this loop when the number of iterations is unknown but you have a condition to control it.

javascriptCopy codelet j = 0;
while (j < animeCharacters.length) {
  console.log(`While Loop: ${animeCharacters[j]}`);
  j++;
}

Output:

vbnetCopy codeWhile Loop: Goku  
While Loop: Naruto  
While Loop: Luffy  
While Loop: Eren  
While Loop: Tanjiro

• How it works:

  1. Initialize j = 0.

  2. Run the loop as long as the condition j < animeCharacters.length is true.

  3. Increment j inside the loop to avoid infinite loops.

Watch out!
If you forget to increment j, you’ll create an infinite loop—a developer’s worst nightmare!

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3. do-while Loop: The Brave First Step

The do-while loop is like Eren from Attack on Titan—it acts at least once, even if failure is inevitable. This loop will run at least one time, even if the condition is false from the start.

javascriptCopy codelet k = 0;
do {
  console.log(`Do-while: ${animeCharacters[k]}`);
  k++;
} while (k < animeCharacters.length);

Output:

vbnetCopy codeDo-while: Goku  
Do-while: Naruto  
Do-while: Luffy  
Do-while: Eren  
Do-while: Tanjiro

• How it works:

  1. The code inside the do block runs once before checking the condition.

  2. If the condition in the while is true, it continues looping.

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Challenge: Loop Through Your Favorite Anime Characters

Now that you know how loops work, try this fun challenge:

1. Create an array of your favorite anime characters (like above).

2. Use all three loops to print them out.

3. Add some fun formatting, like:

   • Print them in reverse order using a loop.

   • Use an if condition inside a loop to highlight your top 1 favorite character!

javascriptCopy codeconst animeCharacters = ['Goku', 'Naruto', 'Luffy', 'Eren', 'Tanjiro'];

for (let i = 0; i < animeCharacters.length; i++) {
  if (animeCharacters[i] === 'Naruto') {
    console.log(`🔥 ${animeCharacters[i]} - My Favorite!`);
  } else {
    console.log(`${animeCharacters[i]}`);
  }
}

Output:

Copy codeGoku  
🔥 Naruto - My Favorite!  
Luffy  
Eren  
Tanjiro

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Bonus: Loop Until You Drop!

• Nested Loops: Loop within a loop—like listing all possible fights between characters.

• Break and Continue:

  • Use break to stop the loop when a condition is met.

  • Use continue to skip a specific iteration.

javascriptCopy codefor (let i = 0; i < animeCharacters.length; i++) {
  if (animeCharacters[i] === 'Eren') break;  // Stop at Eren
  console.log(animeCharacters[i]);
}

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Conclusion

With loops, you can automate actions and handle repetitive tasks efficiently. They’re the backbone of programs that need to process large datasets—whether it's fetching anime titles, processing user input, or animating elements on a webpage. Master loops today, and you’ll unlock limitless power in JavaScript!

Let’s see if you can create a loop-based program with your favorite anime characters! Ready to take on the challenge? 🎌