如何简化这个'for'循环？

Question

val xsa = List(1,2,3)
val xsb = List(1,2,3)
for (i <- 0 until xsa.size) {
    val a = xsa(i)
    val b = xsb(i)
    println(a + "_" + b)
}

我想简化长度等于'List或Array。我希望这样做：

for (a <- xsa; b <- xsb)
    println(a + "_" + b)

但为什么它只迭代xsb一次？

Answer 1

for ((a,b) <- xsa zip xsb)
  println(a + "_" + b)

Answer 2

(xsa, xsb).zipped foreach ((a, b) => println (a + "_" + b))

或者

(xsa, xsb).zipped map (_ + "_" + _) foreach println

Answer 3

尝试Seq.zip

val x = xsa.zip(xsb)
for ((a, b) <- x)
    println(a + "_" + b)