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Dart Academy · Lesson

Logical Operators and Short-Circuiting

Combine conditions with and, or, and not.

Logical Operators and Short-Circuiting is a free Dart Academy lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Dart Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Combining Conditions

Real decisions often depend on more than one thing. Dart lets you join conditions with logical operators to ask richer questions. 🧩

And Means Both

The && operator is true only when both sides are true. If either side is false, the whole expression is false.

bool ok = age >= 18 && hasTicket;

Or Means Either

The || operator is true when at least one side is true. It only turns false when both sides are false.

bool free = isMember || hasCoupon;

Not Flips It

Place ! before a condition to invert it. It is perfect for asking the opposite, like checking that something is not empty.

if (!name.isEmpty) {
  print("Hello");
}

Mixing Operators

You can blend them in one expression. Dart evaluates && before ||, so use parentheses to make your intent crystal clear.

bool allow = isAdmin || (loggedIn && verified);

Short-Circuit With &&

If the left side of && is false, Dart already knows the answer is false. It skips the right side entirely to save work.

if (user != null && user.active) {
  greet(user);
}

Short-Circuit With ||

If the left side of || is true, the result is already true. Dart stops and never evaluates the right side.

if (cached || fetchFromNetwork()) {
  render();
}

Short-Circuiting Protects You

This skipping is more than speed. It lets the left side of && guard the right, avoiding errors like reading a null value.

if (list.isNotEmpty && list.first > 0) {}

Order of the Guard

Because evaluation runs left to right, put the cheaper or safer check first. The order of your conditions truly matters.

if (file != null && file.exists()) {}

Reading Compound Logic

When logic gets dense, store pieces in well-named bool variables. Clear names beat clever one-liners every single time.

bool canEdit = isOwner || isEditor;
if (canEdit) save();

Logic Powers Smart Code

With &&, ||, and !, plus short-circuiting, you can express precise rules and write safer conditions all at once. 🛡️

Quick Check

What does Dart do with the right side of && when the left side is false?

Recap

You learned && for both, || for either, ! to flip, and that short-circuiting skips work and guards against errors. 🎉

Frequently asked questions

Is the “Logical Operators and Short-Circuiting” lesson free?

Yes — the full text of “Logical Operators and Short-Circuiting” is free to read here on the web, and the Dart Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Dart Academy course, upgrade to CoddyKit PRO.

What will I learn in “Logical Operators and Short-Circuiting”?

Combine conditions with and, or, and not. You practise Dart Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Dart Academy?

No prior experience is required. Dart Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Logical Operators and Short-Circuiting” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Dart Academy lesson?

Yes. Every Dart Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. Booleans and Comparison Operators
  2. if, else if, and else
  3. Logical Operators and Short-Circuiting
  4. The Ternary and switch Expression
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