What is Scala's yield?

Question

I understand Ruby and Python\'s yield. What does Scala\'s yield do?

Answer 1

Consider the following for-comprehension

val A = for (i <- Int.MinValue to Int.MaxValue; if i > 3) yield i

It may be helpful to read it out loud as follows

"For each integer i, if it is greater than 3, then yield (produce) i and add it to the list A."

In terms of mathematical set-builder notation, the above for-comprehension is analogous to

which may be read as

"For each integer , if it is greater than , then it is a member of the set ."

or alternatively as

" is the set of all integers , such that each is greater than ."