for Comprehension Basics

for Comprehension Basics

A for comprehension can include multiple generators and filters, like for (x <- 1 to 3; y <- 1 to 3 if x != y) { ... }, iterating over combinations while filtering out unwanted ones inline. This is more powerful than a basic single-generator loop and reads declaratively. Combined with yield (its own tutorial), for comprehensions become a way to build new collections rather than just run side effects.

Note: An if inside a for comprehension's generators filters elements inline, without needing a separate if statement in the body.

Example: for Comprehension Basics

object Main extends App {
  for (x <- 1 to 3; y <- 1 to 3 if x != y) {
    println(s"($x, $y)")
  }
}