scala> // /: or foldLeft() #361, 363
scala> def sum(xs: List[Int]): Int = {
| (7 /: xs) (_ + _)
| }
sum: (xs: List[Int])Int
scala>
scala> val data = List(1, 2, 3)
data: List[Int] = List(1, 2, 3)
scala> sum(data)
res39: Int = 13
scala>
scala> val data = List(1, 2, 3)
data: List[Int] = List(1, 2, 3)
scala> data.foldLeft(7)(_ + _)
res40: Int = 13
scala>
scala> // :\ or foldRight() #361, 363
scala> def sum(xs: List[Int]): Int = {
| (xs :\ 7) (_ + _)
| }
sum: (xs: List[Int])Int
scala>
scala> val data = List(1, 2, 3)
data: List[Int] = List(1, 2, 3)
scala> sum(data)
res41: Int = 13
scala>
scala> val data = List(1, 2, 3)
data: List[Int] = List(1, 2, 3)
scala> data.foldRight(7)(_ + _)
res42: Int = 13
scala>
scala>
scala> // Note/Beware : foldLeft() & foldRight() has difference
scala> // in terms of efficiency #364
scala> // Best Practice : Is intuitive to use foldLeft() instead of
scala> // Symbol /: