• Variables in Rust are, by default, immutable. Immutable variables can be shadowed, but never changed.

  • You can make a variable mutable with the mut keyword in its let statement.

  • Once mutable, you can change the value of a variable with assignment (e.g., x = 5;) and mutation operators (e.g., x += 2;).

  • Mutation is almost always necessary to perform iteration.

  • A while expression is like an if expression, but continues to evaluate the body as long as the condition remains true.

  • You can nest loops inside each other to create more powerful loops.

  • You can use let to declare variables without assigning, though you probably don’t want to.

Get hands-on with 1200+ tech skills courses.