the for-comprehension loops in wrong order with assignment and what is its translation in Scala

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0

given val l = List( List(0), List(1) )

The for-loop :

for {
  x <- l
  _ = println(x)
  y <- x
} {println(y)}

//would prints :

List(0)

List(1)

0

1

Is the prints in the order you expected?

And should not it be translated into the following. the translation of for-loop :

l.foreach(
  x => {
    println(x)
    x.foreach(y => println(y))
  }
)

List(0)

0

List(1)

1

---

My Questions:

1. Why the for-loop is not executed by intuitive order ? (I was expecting the result is of the second example using foreach )


2. Is my translation wrong ?


3. Why we must assign something (e.g. _ = print()) in for-condition part? (just a print() will not compile )

asked 2 mins ago

WeiChing

478

the for-comprehension loops in wrong order with assignment and what is its translation in Scala