> Actually "for" expressions in themselves are actually monad comprehensions - powerful, elegant, but definitely not your grandma's foreach. Also, collections a

> Actually "for" expressions in themselves are actually monad comprehensions - powerful, elegant, but definitely not your grandma's foreach. Also, collections are immutable by default. This definitely threw me for a loop when I started using Scala. I banged my head against the keyboard a few times trying to get for comprehensions to do what I thought they should do. Once I began to fully understand the relationship between for comprehensions and monadic operations, especially on Futures and Options, I began to understand their power.